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Related Manuals for THORLABS EDU-QOP1
Summary of Contents for THORLABS EDU-QOP1
- Page 1 EDU-QOP1(/M) Quantum Optics Kit User Guide...
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Page 3: Table Of Contents
Quantum Optics Kit Table of Contents Chapter 1 Safety ........................... 1 Warning Symbol Definitions ....................1 Laser Radiation Warning ......................1 Piezo Controller Warnings ....................... 1 Chapter 2 Product Description ...................... 2 Chapter 3 Principles of Quantum Optics ..................4 Classical Description of Light .................... - Page 4 Quantum Optics Kit Chapter 4 Experimental Concepts ....................33 Single Photon Detectors ......................33 Time Tagging .......................... 34 4.2.1 Time Tagging versus Coincidence Electronics ....................34 4.2.2 Jitter and Coincidence Window ......................... 34 4.2.3 Delay Compensation ............................35 Chapter 5 Kit Components ......................
- Page 5 Quantum Optics Kit Setting Up the Grangier-Roger-Aspect Experiment ..............84 7.5.1 Beamsplitter Positioning ........................... 85 7.5.2 Third Detector Positioning ..........................86 7.5.3 Third Detector Fine Adjustment ........................86 7.5.4 Test Measurement ............................87 Setting Up the Michelson Interferometer ................88 7.6.1 Additional Alignment Path ..........................89 7.6.2 Interferometer Adjustment ..........................
- Page 6 14.1 Laser System ........................154 14.2 Laser Class Calculation ......................154 14.3 Laser Safety Glasses Calculation ................... 154 Chapter 15 Acknowledgements ....................156 Chapter 16 Warranty and RMA Information ................157 16.1 Return of Devices ......................... 157 Chapter 17 Thorlabs Worldwide Contacts ................... 158...
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Page 7: Chapter 1 Safety
Quantum Optics Kit Chapter 1: Safety Chapter 1 Safety Warning Symbol Definitions Below is a list of warning symbols you may encounter in this manual or on your device Warning: Laser Radiation General Warning Laser Radiation Warning Warning The class 3B laser diode used in this kit can emit more than 50 mW of optical power, which can cause damage to the eyes if viewed directly. -
Page 8: Chapter 2 Product Description
Quantum Optics Kit Chapter 2: Product Description Chapter 2 Product Description The field of quantum physics evolves quickly: quantum computers, quantum cryptography networks, and quantum-based sensing are all nearing introduction into real world applications. Highlighting this, the 2022 Nobel Prize in Physics was awarded to Alain Aspect, John F. Clauser, and Anton Zeilinger for their groundbreaking work in quantum optics. - Page 9 Quantum Optics Kit Chapter 2: Product Description • Single photon interference in a Michelson interferometer • Quantum eraser experiment All these experiments are described in detail in this manual and are made experimentally accessible by clear alignment procedures and experimental alignment tools that greatly help in reliably finding the signals of interest. Rev.
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Page 10: Chapter 3 Principles Of Quantum Optics
Quantum Optics Kit Chapter 3: Principles of Quantum Optics Chapter 3 Principles of Quantum Optics Classical Description of Light In this section, a summary of the classical description of light is given, focused on the properties that play a role in the experiments in this kit. -
Page 11: Interference
(1 − cos ��) �� �� Thorlabs offers the EDU-MINT2(/M) Educational Kit for Classical Interferometry. The manual is freely available on the product webpage and introduces the Michelson interferometer in more detail. M. Fox, Quantum Optics: An Introduction. (Oxford University Press, Oxford, 2006). -
Page 12: Polarization
Quantum Optics Kit Chapter 3: Principles of Quantum Optics It is apparent that the sum of the intensities in the two output arms is always equal to the input intensity �� �� meaning that the energy is conserved. 3.1.3 Polarization The Maxwell equations show that the electromagnetic field is a traverse field, i.e., the field vectors are perpendicular to the propagation direction . - Page 13 Quantum Optics Kit Chapter 3: Principles of Quantum Optics The electric field oscillates along this line, and the light is called linearly polarized. Figure 4 displays an example of a linearly polarized electric field. Figure 4 Electric Field of a Linearly Polarized Wave. The perspective in the right graph is along the negative z-direction (towards the source).
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Page 14: Mathematical Formalism Of Quantum Mechanics
Quantum Optics Kit Chapter 3: Principles of Quantum Optics The polarization of linearly polarized light passing a linear polarizer will be projected onto the polarizer axis, and the intensity will be attenuated according to Malus’ Law: �� = �� ∙ cos (��... -
Page 15: Eigenstates And Eigenvalues
Quantum Optics Kit Chapter 3: Principles of Quantum Optics (�� ̂ + �� ̂ ) | �� ⟩ = �� ̂ | �� ⟩ + �� ̂ | �� ⟩ (30) �� ̂ (| �� ⟩) = �� ̂ | �� ⟩... -
Page 16: Bases Of The Hilbert Space
Quantum Optics Kit Chapter 3: Principles of Quantum Optics [�� ̂ , �� ̂ ] ≡ �� ̂ �� ̂ − �� ̂ �� ̂ (40) If [�� ̂ , �� ̂ ] = 0, the operators are said to be commuting. 3.2.7 Bases of the Hilbert Space In any Hilbert space, there exists at least one orthonormal basis, i.e., a set of vectors |��... -
Page 17: Measurements And Superposition Of Quantum States
Quantum Optics Kit Chapter 3: Principles of Quantum Optics 3.2.9 Measurements and Superposition of Quantum States Hidden in the prior subsection is an integral property of quantum physics, the superposition of states. As stated previously, measuring an observable �� of a particle in the state |��⟩ can in general result in any eigenvalue �� ��... -
Page 18: Combination Of Quantum Systems
Quantum Optics Kit Chapter 3: Principles of Quantum Optics The �� are the weights for the pure state and can be interpreted as the probabilities of the mixed state to behave �� as if being in the corresponding pure state when an observable is being measured. Note that they are not the probability of the mixed state being the pure state. -
Page 19: Coherent States
Quantum Optics Kit Chapter 3: Principles of Quantum Optics fundamental excitations of the electromagnetic field. They are the eigenstates | �� ⟩ of the Hamiltonian and of the number operator: �� ̂ | �� ⟩ = �� | �� ⟩ ��... -
Page 20: Thermal States
Quantum Optics Kit Chapter 3: Principles of Quantum Optics distribution of the photon numbers. Indeed, it can be proven that the probabilities of a coherent state measured in different Fock states is Poissonian , as depicted in the center graph of Figure 6. 3.3.3 Thermal States Besides Fock states and coherent states, there are other, more chaotic states of light. -
Page 21: Second-Order Correlation Function
Quantum Optics Kit Chapter 3: Principles of Quantum Optics the light field is still defined by the classical Maxwell equations. Therefore, different experiments are required to test the quantum nature of light. 3.4.1 Second-Order Correlation Function A conceptually simple test is to send a light beam with extremely low intensity through a beamsplitter with two detectors at the two possible outputs of the splitter. -
Page 22: Quantum Mechanical Treatment Of A Beamsplitter
Quantum Optics Kit Chapter 3: Principles of Quantum Optics into two parts with a constant ratio. The signals at the detectors can then either be uncorrelated (amplitude constant in time) or correlated (amplitude varies in time, both detectors “see” the same increase and decrease of the signal) and there is no way that the signal on one detector increases while the signal on the other decreases. -
Page 23: Quantum Fields
Quantum Optics Kit Chapter 3: Principles of Quantum Optics 3.4.3 Quantum Fields ( 0 ) in an intensity interferometer cannot be smaller than 1, as shown in Section 3.4.1. In this Classically, �� ( 0 ) are derived depending on the characteristics of the incoming section, the limits and expected values of ��... -
Page 24: Proof Of Quantized Light - Experiment
Quantum Optics Kit Chapter 3: Principles of Quantum Optics can never be detected at the other output. This agrees with intuition: as the photon is the smallest possible excitation of the electromagnetic field, it cannot be split further. This can be experimentally confirmed in this kit; see Section 9.4. -
Page 25: Correlation Function For Single Photon Detectors
Quantum Optics Kit Chapter 3: Principles of Quantum Optics Please note that this value can only be measured in the limit of idealized detectors with perfect time resolution. ( 0 ) towards the limit of 1, as seen in The time resolution of real detectors will reduce the measured value of �� ������... -
Page 26: Grangier-Roger-Aspect Experiment
Quantum Optics Kit Chapter 3: Principles of Quantum Optics ( 0 ) term always remain is no difference between the two. Most importantly, the inequalities that include the �� ������ valid. For thermal sources (see Section 3.3.3), the time-dependent correlation function drops from 2 at �� = 0 to 1 for ��... -
Page 27: Triple Coincidence Detection Scheme
Quantum Optics Kit Chapter 3: Principles of Quantum Optics Figure 10 Schematic of the Grangier-Roger-Aspect Experiment ( 0 ) = 0.18, a result that can only be explained by the quantization of Using this approach, they obtained �� ������ the electromagnetic field (the subscript GRA indicates the change in setup compared to a HBT intensity interferometer). -
Page 28: Triple Coincidence Detection Scheme: Explanation 1
Quantum Optics Kit Chapter 3: Principles of Quantum Optics �� �� �� ���� ���� ������ �� �� �� (100) �� �� ���� �� �� �� �� �� �� Substituting this into Equation (99), the result is: �� ∙ �� ������ ��... -
Page 29: Accidental Coincidences
Quantum Optics Kit Chapter 3: Principles of Quantum Optics 0.01 Here, we used the relation �� which can be derived from Equation (103) and the fact that the rates are the �� ∆�� �� ���� numbers divided by the measurement time, e.g. �� . -
Page 30: Single Photon Interference
Quantum Optics Kit Chapter 3: Principles of Quantum Optics • Shorten the coincidence window. This is limited by the time resolution of the detectors and electronics. In the case of this kit, the jitter of the EDU Time Tagger is 720 ps (see Section 4.2.2), so coincidence windows shorter than 1 ns do not improve the result. -
Page 31: Experimental Realization
Quantum Optics Kit Chapter 3: Principles of Quantum Optics The state after recombination is then: ���� | �� ⟩ = ( | 1 ⟩ | 0 ⟩ + �� | 0 ⟩ |1⟩ ������ �� �� �� �� √ 2 †... -
Page 32: Quantum Treatment Of Polarization
Quantum Optics Kit Chapter 3: Principles of Quantum Optics Mirror 1 is positioned on a movable stage. In the experiment, the stage position and therefore the path length difference ∆�� is varied and the coincidence count rate �� is plotted. The expected count rate is then a function ����... -
Page 33: Experimental Realization
Quantum Optics Kit Chapter 3: Principles of Quantum Optics �� ( θ ǁ �� ) = |⟨ θ | �� ⟩| (126) It is instructive to look at the special case of in the incoming photon being linearly polarized with an angle ��, i.e., in the state |��⟩. -
Page 34: The Quantum Eraser
Quantum Optics Kit Chapter 3: Principles of Quantum Optics The Quantum Eraser 3.8.1 Theoretical Description In Section 3.6, we discussed the Michelson interferometer. What happens when we insert polarizers into the interferometer? This will link polarization with the information about the interferometer arms. To demonstrate that, we will use combined states of the form |��... -
Page 35: Experimental Realization
(SPDC) to generate photon pairs. In SPDC, pairs of photons are generated inside a nonlinear crystal from pump Thorlabs offers the EDU-QE1(/M) Quantum Eraser Analogy Kit. The manual is freely available on the product webpage and introduces the quantum eraser experiment in more detail. - Page 36 Quantum Optics Kit Chapter 3: Principles of Quantum Optics light, typically the output of a pump laser. These photons are created virtually simultaneously, so that one of the photons can be used to signal the existence of the other, making it possible to perform measurements on single photons.
- Page 37 Quantum Optics Kit Chapter 3: Principles of Quantum Optics The refractive index as a function of the wavelength for BBO is shown in Figure 15. The red solid curve marks the refractive index for the ordinary beam (n ). The black dashed curve is the refractive index for the extraordinary beam (n ) if the input beam is orthogonal to the crystal plane.
- Page 38 Quantum Optics Kit Chapter 3: Principles of Quantum Optics When measuring with two detectors in coincidence, one must be careful that the detectors are positioned in such a way that they are able to detect photons from the same pair. Furthermore, when measuring wavelength- dependent quantities like the coherence length of the SPDC generated photons, one must consider that the wavelengths are spatially separated.
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Page 39: Chapter 4 Experimental Concepts
Geiger mode) but works at much lower photon energies. This output pulse is often shaped by internal electronics of the detector to match an international standard, such as TTL. A typical output pulse of Thorlabs' SPDMA Single Photon Detection Module, included in this kit, is displayed on the left graph of Figure 18. -
Page 40: Time Tagging
Quantum Optics Kit Chapter 4: Experimental Concepts Time Tagging 4.2.1 Time Tagging versus Coincidence Electronics A fundamental part of doing quantum optic experiments with a photon pair source is the counting of coincidence events. There are two main technical implementations to determine whether two events are temporally close enough to be counted as a coincidence: 1.) Coincidence Electronics: By constructing a gated circuit with serial logic elements or on a field programmable gate array (FPGA), one can count events in which the pulses of two detectors arrive in a... -
Page 41: Delay Compensation
Quantum Optics Kit Chapter 4: Experimental Concepts Figure 19 Definition of a Coincidence Between Two Channels of the Time Tagger (Bars Mark the Length of the Coincidence Window). The dashed rectangle marks an unwanted case of two coincidences created by only one event in Channel A. - Page 42 Quantum Optics Kit Chapter 4: Experimental Concepts 1.) Arbitrary delays caused by jitter in the detectors and timing electronics. 2.) Systematic delays caused by different cable lengths, slight differences in detector circuits, differences in the path lengths to the detectors (30 cm ≈ 1 ns for light in air), etc. The systematic delays are often much larger than the arbitrary ones (on the order of several ns) but can be compensated for by just adding or subtracting a constant time from every timestamp on a given channel before calculating coincidences.
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Page 43: Chapter 5 Kit Components
Pre-selected to be within ±1 nm. This laser diode comes with a spec sheet that includes the LIV curve. The EDU-QOP1/M kit comes with a 30.1 mm tall post holder. For a replacement, please contact Tech Support (techsupport@thorlabs.com). Rev. A, June 16, 2023... -
Page 44: Crystal And Adjustment Aids
2" (50 mm) Long This is a KM100CP(/M) mount with extra engravings. For a replacement, please contact Tech Support (techsupport@thorlabs.com). The EDU-QOP1/M kit comes with a 30.1 mm tall post holder. For a replacement, please contact Tech Support (techsupport@thorlabs.com). Page 38... - Page 45 This is a modified ID15(/M) iris where the TR3 (TR75/M) post is not included. For a replacement, please see the ID15(/M) iris on the website. This is a modified ID25(/M) iris where the TR3 (TR75/M) post is not included and a longer 8-32 (M4) setscrew is utilized. For a replacement, please contact Tech Support (techsupport@thorlabs.com). Rev. A, June 16, 2023...
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Page 46: Detectors
Quantum Optics Kit Chapter 5: Kit Components 1 x PH082E (PH20E/M) 1 x TR075 (TR20/M) 1 x RS4M (RS5M) 2 x RS10M Ø1/2" (Ø12.7 mm) Ø1/2" (Ø12.7 mm) Post, Spacer for Ø25 mm Spacer for Ø25 mm Posts, Pedestal Post Holder, 0.75"... -
Page 47: Michelson Interferometer
Quantum Optics Kit Chapter 5: Kit Components 3 x DTSM1 3 x SM1NT1 3 x PH2E (PH50E/M) 3 x TR2 (TR50/M) External SM1 Threads to SM1 (1.035"-40) Ø1/2" (Ø12.7 mm) Ø1/2" (Ø12.7 mm) Post, Female D4T Dovetail Locking Ring, 1.25" Pedestal Post Holder, 2"... -
Page 48: Time Tagger And Software
3 x CA2924 1 x USB Stick SMA Coaxial Cable Male-to-Male EDU-QOP1 Software 24" (609 mm) Long This is a modified ID15(/M) iris where the TR3 (TR75/M) post is not included. For a replacement, please see the ID8(/M) iris on the website. -
Page 49: Quantum Eraser
Quantum Optics Kit Chapter 5: Kit Components Quantum Eraser 2 x LPNIRB050 1 x LPNIRE100-B 1 x WPH10ME-808 4 x RSP1D(/M) Ø1/2" Unmounted Linear Ø1" Unmounted Linear Ø1" Mounted Polymer Rotation Mount for Polarizer, 650 - 1100 nm Polarizer, Zero-Order Half-Wave Ø1"... -
Page 50: Included Hardware
Quantum Optics Kit Chapter 5: Kit Components 1 x SPW502 1 x CS1 1 x LG3 1 x Label Sheet Spanner Wrench for Slotted SM05, Screw-On Cable Laser Safety Glasses SM1, and C-Mount Locking Rings Straps (Qty. 15) Included Hardware 5.9.1 Imperial Kit To Combine Components... -
Page 51: Chapter 6 Quick Setup
Quantum Optics Kit Chapter 6: Quick Setup Chapter 6 Quick Setup This chapter provides a summary of the setup procedure for experienced users or as a reminder when rebuilding the setup several times. The assembly of the components is explained in Section 7.1 and a detailed guide to building the setup is provided in the remainder of Chapter 7. - Page 52 Quantum Optics Kit Chapter 6: Quick Setup GRA Experiment (Section 7.5) • Align a beamsplitter in the path to detector A and position detector B in the other output of the splitter. • Position detector B analog to detectors T and A (axicon → filter → BBO). •...
- Page 53 Quantum Optics Kit Chapter 6: Quick Setup Figure 25 Complete Setup Overview. The numbers in parentheses are breadboard hole numbers (from left / from bottom). Rev. A, June 16, 2023 Page 47...
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Page 54: Chapter 7 Setup And Adjustment
Quantum Optics Kit Chapter 7: Setup and Adjustment Chapter 7 Setup and Adjustment This chapter gives detailed and thorough instructions for setting up all the components and experiments in the kit. Chapter 6 offers a very brief summary for experienced users or repeated rebuilds. 7.1 Assembly of Components 7.1.1 Pump Laser... - Page 55 Quantum Optics Kit Chapter 7: Setup and Adjustment o During step 6, use a 5/64" (2 mm) hex key to screw the setscrew as far into the post as possible. o In step 7, use the torque hole of the post to tighten the connection between LDM9T(/M) mount and the post.
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Page 56: Alignment Laser
• Please note: o The KM100CP(/M) mirror mount has two threaded bases. Attach the one labeled “Thorlabs” to the magnetic plate (as shown as step 2 in Figure 29). This allows better access to the adjusters when placed in the setup. -
Page 57: Mirrors
Quantum Optics Kit Chapter 7: Setup and Adjustment 7.1.3 Mirrors • Assemble two mirror setups as shown in Figure 30, one as shown in Figure 31, and one as shown in Figure • Please note: o The cap screws that connect the KM100 mount to the KCP1(/M) plate are included with the KM100 mount. -
Page 58: Iris Apertures
Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 32 Third Mirror Assembly (Build One) 7.1.4 Iris Apertures • Assemble three iris aperture assemblies as shown in Figure 33. Figure 33 Iris Aperture Components Page 52 MTN036012-D02... -
Page 59: Half-Wave Plates
Quantum Optics Kit Chapter 7: Setup and Adjustment 7.1.5 Half-Wave Plates • Assemble the wave plates as shown in Figure 34. • Please note: o During step 1, use a 5/64" (2 mm) hex key to screw the setscrew as far into the RSP1D(/M) rotation mount as possible. -
Page 60: Crystal, Axicon, And Filter
Quantum Optics Kit Chapter 7: Setup and Adjustment 7.1.6 Crystal, Axicon, and Filter • Remove the retaining ring from an SM05L10 lens tube and assemble the axicon as shown in Figure 35. • Please note: o In step 1, the conical side of the axicon should face the bronze spacers (see Figure 36). Only touch the circumference of the axicon. - Page 61 Quantum Optics Kit Chapter 7: Setup and Adjustment • Assemble the BBO Crystal as shown on the left side of Figure 37. • Please note: o During step 1, make sure to align the marked edges as parallel as possible. o Make sure to align the crystal with respect to the markings on the KM100CP(/M) mount as shown on the right side of Figure 37.
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Page 62: Beamsplitter
Quantum Optics Kit Chapter 7: Setup and Adjustment 7.1.7 Beamsplitter • Assemble the beamsplitters as shown in Figure 39. • Please note: o Before step 4 on the left side of Figure 39, use a 0.05" (1.3 mm) hex key to tighten the locking screw of the SM1D12 iris. -
Page 63: Detector Optics
Quantum Optics Kit Chapter 7: Setup and Adjustment 7.1.9 Detector Optics • Assemble three detector optics as shown in Figure 41. • Please note: o Before beginning the assembly, remove the SM05RR retaining ring from the SM1NR05 zoom housing and the SM1RR retaining ring from the SM1L05 lens tube. o During step 1, the convex side of the lens should face the SM1NR05 (see Figure 41). -
Page 64: Beam Trap
Quantum Optics Kit Chapter 7: Setup and Adjustment 7.1.10 Beam Trap • Assemble the beam trap as shown in Figure 42. • Please note: o In step 1, screw the setscrew all the way into the SMR1(/M) mount. Use a 9/64" (3 mm) hex key. -
Page 65: Economy Beamsplitter
Quantum Optics Kit Chapter 7: Setup and Adjustment 7.1.12 Economy Beamsplitter • Remove the retaining ring from an SM1L03 lens tube and assemble the economy beamsplitter as shown in Figure 44. • Please note: o Only touch the circumference of the beamsplitter. Do not touch the beamsplitter surface. o For step 2, use an SPW606 spanner wrench. -
Page 66: Mirrors For Michelson Interferometer
Quantum Optics Kit Chapter 7: Setup and Adjustment 7.1.14 Mirrors for Michelson Interferometer • Assemble the mirror on the stage as shown in Figure 46. • Please note: o During step 2, make sure that you are using the correct screw length. Longer screws may damage the stage! o During steps 2 and 3, make sure that the edges marked in Figure 46 are aligned as parallel as possible. -
Page 67: Lens
Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 47 Second Mirror for Michelson Interferometer 7.1.15 Lens • Unscrew the retaining ring from an LMR1(/M) lens mount and assemble the alignment lens as shown in Figure 48. • Please note: o During step 3, make sure to touch the lens only on the outer circumference. -
Page 68: Mounting The Led
Quantum Optics Kit Chapter 7: Setup and Adjustment 7.1.16 Mounting the LED • Assemble the LED as shown in Figure 49. • Please note: o During step 3, take care of the polarity of LED and mount. The correct orientation is shown in Figure 50. -
Page 69: Polarizers For Quantum Eraser
Quantum Optics Kit Chapter 7: Setup and Adjustment 7.1.17 Polarizers for Quantum Eraser • Remove the retaining ring from an RSP1D(M) mount and assemble a polarizer component as shown in Figure 51. • Please note: o During step 1, use a 5/64" (2 mm) hex key to screw the setscrew as far into the RSP1D(/M) mount as possible. -
Page 70: Labelling The Time Tagger
Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 52 Small Polarizer Assembly 7.1.18 Labelling the Time Tagger • Use the label sheet to label the first three channels of the Time Tagger as shown in Figure 53. o Channel 1 → T o Channel 2 →... -
Page 71: Preliminary Alignment
Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 54 Detector Labeling Preliminary Alignment 7.2.1 Software Installation • Install the software of the kit as described in Section 11.1. 7.2.2 Collimating the Pump Laser • Place the pump laser on the left side of the breadboard pointing to the right and secure its position with a CF125 clamp and a 1/4"-20 x 3/8"... - Page 72 Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 56 Maximum Current Setting for the KLD101 Controller • Turn the key on the KLD101 controller and set the laser current to 15 mA by turning the wheel on the controller. •...
- Page 73 Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 58 Laser on Screen Before Collimation • Use the SPW909 spanner to rotate the lens adapter in front of the pump laser clockwise to change the lens position, decreasing the laser divergence until the laser on the screen looks like the one in Figure 59. Figure 59 Laser Spot on Screen After Collimation (Left) and Zoomed View (Right) •...
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Page 74: Calibrating The Polarizer
(122° in the example in Figure 62). Figure 62 Polarizer after Minimizing Transmission • Switch the front and back sides of the polarizer component, as seen in Figure 63. A video detailing the process is available at: https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=14062#VideoPolarizerHVAlign Page 68 MTN036012-D02... - Page 75 Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 63 Polarizer after Rotation • Rotate the polarizer until the intensity on the screen is minimized and note the value on the scale. • Rotate the polarizer to the position exactly in the middle of the two scale values you noted, then tighten the locking screw of the rotation mount.
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Page 76: Setting Up The Hbt Experiment With The Alignment Laser
Quantum Optics Kit Chapter 7: Setup and Adjustment Setting Up the HBT Experiment with the Alignment Laser As a first experiment, it is recommended to show that an attenuated laser is not suitable as a single photon source. The experimental setup is shown schematically in Figure 65. Figure 65 Schematic of the HBT Experiment with the Alignment Laser Set this experiment up as follows:... - Page 77 Quantum Optics Kit Chapter 7: Setup and Adjustment • Figure 67 shows the back side of the target before alignment. The clear red spot is the reflection from the beamsplitter. There can be a diffuse red spot which is the reflection from the detector chip and can be ignored.
- Page 78 Quantum Optics Kit Chapter 7: Setup and Adjustment • Rotate the zoom housing of the left detector (when looking from the perspective of the filter) to about the middle of its range (test how far it can be turned in both directions and then try to turn it halfway from one endpoint).
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Page 79: Setting Up The Photon Pair Source
Quantum Optics Kit Chapter 7: Setup and Adjustment Setting Up the Photon Pair Source In this Section, the photon pair source is set up. This source forms the basis of all quantum optic experiments in this kit. In Figure 69, an overview of the photon pair setup is given. The following subsections include detailed instructions for the placement and adjustment of the components. - Page 80 Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 71 Setup after Placement of First Pump Laser Mirror • Switch on the LDM9T(/M) mount. Set the temperature knob to 25°C. • Switch on the KLD101 driver and set the laser current to 15 mA. Switch on the pump laser via the button on the KLD101 driver.
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Page 81: Aligning Both Pump And Alignment Laser On The Same Path
Quantum Optics Kit Chapter 7: Setup and Adjustment • The cards included in the K-Cube controller packages can be used to see the laser spot while centering the beam on the mirror, as shown in Figure 73. Figure 73 Alignment on The Mirror •... - Page 82 Quantum Optics Kit Chapter 7: Setup and Adjustment • Place a mirror (with a KCP1(/M) mount, without a magnetic base) on the 6 breadboard hole from the left and 13 from the front. It should be angled by 45°, so that the alignment laser is reflected towards the far edge of the breadboard.
- Page 83 Repeat all the above steps iteratively until the alignment laser is centered on both iris apertures as shown in Figure 77. Figure 77 Beam Path after Successful Beamwalk For more details and a video, see https://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=14221 Rev. A, June 16, 2023 Page 77...
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Page 84: Detector Positioning
Quantum Optics Kit Chapter 7: Setup and Adjustment • Switch off the alignment laser and remove the mirror from the magnetic base. • The next step is to align the pump laser on the exact same beam path as the alignment laser, as defined by the two iris apertures. - Page 85 Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 79 Axicon Pattern Before (left) and After (right) Alignment • It is important that the alignment laser hits the axicon under normal incidence. To ensure this, close the iris in front of the axicon almost completely and watch the reflection of the axicon on the back side of the iris as shown in Figure 80.
- Page 86 Quantum Optics Kit Chapter 7: Setup and Adjustment o The reflection from the beamsplitter passes back through the hole of the target. o The light passing the hole of the target is centered on the detector chip, as seen in Figure 81. Figure 81 Laser Spot Centered on Detector Chip Figure 82 shows the back side of the target before alignment.
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Page 87: Detector Fine Adjustment
Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 83 Setup after Detector Placement • Take one of the prepared detector optics and loosen the locking screw of the DTSM1 dovetail adapter almost completely. Slide it over the dovetail adapter on the front of the detector labeled “T” (closer to the far breadboard edge). - Page 88 (labeled T and A, respectively). The detector and channel labeling should match. • Connect the KLD101 driver and Time Tagger to your PC via the included USB cables. Start the EDU-QOP1 Software. Switch on both detectors and wait for the Signal LEDs to turn green. Open the iris apertures of both detector optics completely.
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Page 89: Crystal Angle Adjustment
Quantum Optics Kit Chapter 7: Setup and Adjustment • Once you have found the maximum in one axis, optimize further with the other differential screw. • Once you have maximized the count rate via the differential screws, carefully turn the zoom housing again to further increase the count rate. -
Page 90: Setting Up The Grangier-Roger-Aspect Experiment
Quantum Optics Kit Chapter 7: Setup and Adjustment • If the count rates show maxima at significantly different screw positions (and no significant increase of the coincidence count rates is observed), the detectors are not symmetrically placed, and you need to remove both detectors and repeat the positioning process. -
Page 91: Beamsplitter Positioning
Quantum Optics Kit Chapter 7: Setup and Adjustment components. The following subsections give detailed instructions for the placement and adjustment of those components. Figure 88 Setup for the GRA Experiment. Added Components are Marked with a Rectangle. The numbers in parentheses are breadboard hole numbers (from left / from bottom). Components are not to scale and exact positions may deviate slightly from those given in text. -
Page 92: Third Detector Positioning
Quantum Optics Kit Chapter 7: Setup and Adjustment • Check that the laser is still aligned to the center of the beamsplitter iris, then secure the position of the beamsplitter with a CF125 clamp and a 1/4"-20 x 3/8" (M6 x 10 mm) cap screw plus washer. 7.5.2 Third Detector Positioning •... -
Page 93: Test Measurement
Quantum Optics Kit Chapter 7: Setup and Adjustment screws of the CXY1A mount in both directions until you observe a significant increase in the count rate of detector B in the software. If you see such a signal increase, then maximize the signal. If you do not see a signal increase, return the screw to the center position (align the marks on the front side of the CXY1A mount) and try the other differential screw. -
Page 94: Setting Up The Michelson Interferometer
Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 91 Setup for Malus’ Law Experiment Setting Up the Michelson Interferometer In this Section, a Michelson interferometer for single photons (see Section 3.6) is constructed. In Figure 92, an overview over the setup is given, with the red rectangles marking the newly added or moved components. Figure 92 Overview over the Michelson Interferometer Setup. -
Page 95: Additional Alignment Path
Quantum Optics Kit Chapter 7: Setup and Adjustment 7.6.1 Additional Alignment Path Before setting up the interferometer, it is helpful to set up a second alignment path for the alignment laser, following the way the photons take from the crystal to the beamsplitter. Do this as follows: •... -
Page 96: Interferometer Adjustment
Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 94 Additional Alignment Path After Completed Alignment (Beam Centered on Both Apertures) 7.6.2 Interferometer Adjustment In the following steps we are going to set up the Michelson interferometer breadboard. Figure 95 shows how the board will look like after setting up the interferometer completely. - Page 97 Quantum Optics Kit Chapter 7: Setup and Adjustment • Rotate the board such that the mirror on the stage faces the target. Switch on the alignment laser and adjust the board position such that the beam hits the center of the mirror, and the reflection passes back through the hole in the alignment target.
- Page 98 Quantum Optics Kit Chapter 7: Setup and Adjustment • Rotate and move the mirror until the alignment laser is centered on the mirror and you see its reflection on the back side of the alignment target. Then secure the mirror position with a CF125 clamp via a 1/4"-20 x 3/8"...
- Page 99 Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 98 Alignment of Interferometer Arms • Adjust the kinematic screws of one of the mirrors in the interferometer. You will see one of the bright spots moving. Adjust the mirror until the moving spot overlaps with the internal reflection spot. Then repeat this for the other interferometer mirror until you see only one bright spot on the screen, as shown on the right side of Figure 99.
- Page 100 Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 99 Spots on the Screen Before (Left) and After (Right) Adjustment of the Interferometer Mirrors • Place the Ø1" lens assembly between the alignment laser and the interferometer as seen in Figure 100. Adjust the lens height and position so that the alignment laser is centered on the lens.
- Page 101 Quantum Optics Kit Chapter 7: Setup and Adjustment • You will probably see multiple interference rings (similar to the left side of Figure 101). This means that there is a significant difference between the arm lengths of the interferometer. Loosen the CF125 clamp of the mirror not on the stage and move the mirror slightly further away from the beamsplitter, then secure the clamp again.
- Page 102 Quantum Optics Kit Chapter 7: Setup and Adjustment • Probably, you will not yet see an interference pattern on the screen. Move the fine adjuster of the differential screw of the stage (see Figure 103) very slowly (about 2 small scale markers per second) in one direction, until an interference pattern appears .
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Page 103: Detector Positioning
Quantum Optics Kit Chapter 7: Setup and Adjustment 7.6.3 Detector Positioning • Remove the LED and switch on the alignment laser. Remove the screen. Use the screen to block the arm of the Michelson Interferometer that leads to the mirror not on the stage, as seen in Figure 105. •... -
Page 104: Single Photon Interference Adjustment
Quantum Optics Kit Chapter 7: Setup and Adjustment • Find the maximum count rate for detector B just like you did before by turning the two kinematic screws of the CXY1A mount and the zoom housing. To avoid inconvenient scaling of the graphs, temporarily deactivate the curves of detectors T and A (right click on the legend and deactivate the Plot Visible option). -
Page 105: Michelson Interferometer Test Measurement
Quantum Optics Kit Chapter 7: Setup and Adjustment 7.6.6 Michelson Interferometer Test Measurement • Remove the bottom plates from the KPZ101 controller and KSG101 strain gauge reader and fix them to the breadboard to the right next to the KLD101 controller with two 1/4"-20 x 3/8" (M6 x 10 mm) cap screws and washers each. -
Page 106: Setting Up The Quantum Eraser
Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 107 Typical Result of Michelson Test Measurement • If you see the interference, then your Michelson Interferometer is aligned. For more details on the Michelson experiment, see Sections 3.6 and 9.7. Setting Up the Quantum Eraser As a first step, the two Ø1/2"... - Page 107 Quantum Optics Kit Chapter 7: Setup and Adjustment plate and block the beam both behind the wave plate and in front of detector A either with cards (as shown in Figure 108) or with the screen. • Rotate the wave plate component until the reflection from it passes back through the hole in the target, as seen in Figure 108.
- Page 108 Quantum Optics Kit Chapter 7: Setup and Adjustment Figure 109 Positioning of Polarizer in Interferometer • Repeat the above step for the second polarizer in the other arm of the interferometer (use a short clamp instead of a CF125 clamp). Set this polarizer to 0° as well. Remove the target from the breadboard, switch off the alignment laser, and transfer the laser to its original position in the setup.
- Page 109 Quantum Optics Kit Chapter 7: Setup and Adjustment • Perform the same test measurement as described in the last step of Section 7.6.6. If you see the interference minima and maxima, you have adjusted the Quantum Eraser. For more details on this experiment, see Sections 3.8 and 9.8.
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Page 110: Chapter 8 Learning Goals And Misconceptions
Quantum Optics Kit Chapter 8: Learning Goals and Misconceptions Chapter 8 Learning Goals and Misconceptions Since quantum optics is both an exciting and challenging topic, the following table summarizes the experiments and the learning goals. Exercise Experiment Learning Goal Possible Misconception People tend to have the misconception that laser light is just a barrage of photons, visualized as little dots. - Page 111 Quantum Optics Kit Chapter 8: Learning Goals and Misconceptions But how does this work for single photons since they cannot be split into two parts? In quantum optics, the photon’s polarization state is expressed by a superposition of basis states. The proportionate transmission of a classical wave is replaced by the probability of transmitting through the polarizer.
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Page 112: Chapter 9 Experiments
Quantum Optics Kit Chapter 9: Experiments Chapter 9 Experiments In this chapter, experiments that can be performed with the kit are described in detail. The learning goals of the experiments and common misconceptions that may be worth addressing in a lab course are summarized in Chapter 8. -
Page 113: Photon Pair Source
Quantum Optics Kit Chapter 9: Experiments �� �� = ∙ �� �� In our case, we measure about 300 kHz of count rate at both detectors, so the overall frequency �� would be 600 kHz. The setup is about 1 m long. We get as a result: ��... -
Page 114: Hbt Experiment With One Arm Of The Pair Source
Quantum Optics Kit Chapter 9: Experiments HBT Experiment with one Arm of the Pair Source Goal: Test if one arm of the photon pair source is a single photon source. Setup: Take the setup from Section 9.2, place a beamsplitter in one of the detection arms and place single photon detectors at both outputs of the beamsplitter, see Figure 113. -
Page 115: Gra Experiment With Classical Light
Quantum Optics Kit Chapter 9: Experiments Figure 114 Schematic Setup for the Grangier-Roger-Aspect Experiment Measurement: Darken the room and open the GRA tab in the software. Set the measurement time to 1 s, perform 10 measurements, and record the results of each measurement. Then set the measurement time to 10 s and again record ten measurements. -
Page 116: Malus' Law For Single Photons
Quantum Optics Kit Chapter 9: Experiments Setup: Use the setup of Section 9.4 and replace the BBO crystal with the fluorescent filter. The filter will emit fluorescent light in all directions, so that you can perform the GRA experiment with it. A schematic of the setup is shown in Figure 115. -
Page 117: Single Photon Michelson Interferometer
Quantum Optics Kit Chapter 9: Experiments Measurement: Set the polarizer to 0°. Darken the room and open the GRA Tab in the software. Set the ( 2 ) measurement time to 10 s and record a measurement (the important data points are �� (0) and ��... - Page 118 Quantum Optics Kit Chapter 9: Experiments Figure 118 Schematic Setup for the Single Photon Michelson Interferometer Measurement: Darken the room and open the Michelson Tab in the software. Start a measurement with a long range of stage positions (for example 2 µm - 18 µm), a short integration time (such as 400 ms) and a medium step width (such as 25 nm).
- Page 119 Quantum Optics Kit Chapter 9: Experiments Michelson Interferometer Coincidences 9 10 11 12 13 14 15 16 17 18 19 Stage Position (µm) Michelson Interferometer g (0) GRA 0.20 0.15 0.10 0.05 0.00 9 10 11 12 13 14 15 16 17 18 19 Stage Position (µm) Figure 119 Michelson Interferometer Measurement (Range: 2 µm - 18 µm;...
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Page 120: Quantum Eraser
Quantum Optics Kit Chapter 9: Experiments Short Range Michelson Coincidences 10.0 10.5 11.0 Stage Position (µm) Figure 120 Michelson Measurement (Range: 9 µm - 11 µm, Step Size: 10 nm, Time per Data Point: 1200 ms) Quantum Eraser Goal: Show the quantum eraser effect for single photons. Setup: Take the setup from Section 9.7 and place one 1/2"... - Page 121 Quantum Optics Kit Chapter 9: Experiments Measurement: Set both polarizers to 0°, darken the room, and open the Michelson Tab in the software. Set the start and end positions of the stage at about 1 µm apart. Record a measurement. Rotate one of the polarizers to 90°...
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Page 122: Chapter 10 Additional Experiments
Quantum Optics Kit Chapter 10: Additional Experiments Chapter 10 Additional Experiments 10.1 Coherence Length The coherence length �� of a light source can be determined by evaluating the envelope of the interferogram taken �� with the source, as seen in Figure 123. How to Determine the Coherence Length ��... - Page 123 An additional experiment could be to exchange the bandpass filters in front of all three detectors with filters with a broader window, such as Thorlabs’ FBH800-40 filter. This way, the coherence lengths would decrease, so that the “true” spectrum of the SPDC source could be measured even with a single interferogram over the whole piezo range.
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Page 124: The Three-Polarizer-Paradox
Quantum Optics Kit Chapter 10: Additional Experiments Figure 126 Michelson Measurement with FBH800-40 Filters, Envelope Maximum at 1 µm 10.2 The Three-Polarizer-Paradox The three-polarizer-paradox describes a situation where the transmission through two crossed polarizers is zero. Upon adding a third polarizer at 45° rotation (with respect to the polarization axis of the other two polarizers) in between, the intensity increases again. -
Page 125: Qubits And Gates
Quantum Optics Kit Chapter 10: Additional Experiments In the following, we give a short description of basic quantum computing algorithms with a strong focus on the general concept and the concrete technical implementation based on this kit. It is important to note that these algorithms can only deliver answers to highly specialized problems and are by no means suitable for general purpose calculations we are used to from modern PCs. -
Page 126: Deutsch-Jozsa Algorithm
Quantum Optics Kit Chapter 10: Additional Experiments | 1 ⟩ : | 0 ⟩ ↔ | 1 ⟩ �� �� �� Such multi-qubit operations can create system states that cannot be written as simple products of the single qubit states (separable states). Such states can be mixed or entangled qubit states. In photonic QC, various properties of a single photon can be used to represent orthogonal bases for qubits. -
Page 127: Optical Implementation
Quantum Optics Kit Chapter 10: Additional Experiments Figure 127 The four possible functions for the Deutsch algorithm: constant (left) or balanced (right) output. One possible two-qubit quantum circuit which solves the Deutsch problem is shown in Figure 128. The two rows show the operations done on each qubit from left to right. - Page 128 Quantum Optics Kit Chapter 10: Additional Experiments Figure 129 Scheme for the optical implementation of the Deutsch algorithm in a Mach-Zehnder interferometer configuration. The color-highlighted elements correspond to elements of the quantum circuit in Figure 128. Here, the first qubit state | �� ⟩ is represented by the two path states of the single photon in an interferometer and the qubit | ��...
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Page 129: Experimental Realization
These screws can be ordered as packs of 50 under the part number SS8S075 (SS4MS20). When using the Kinesis software, do not connect to the KLD101, KSG101, and KPZ101 controllers, otherwise the EDU-QOP1 software cannot connect to them. We recommend starting the EDU-QOP1 software first; then only the KLC101 controllers will be listed in Kinesis. - Page 130 Quantum Optics Kit Chapter 10: Additional Experiments Figure 130 shows the implementation of the DJA based on this kit, using two LCC1111-B liquid crystal retarders and KLC101 liquid crystal controllers. The HWP between the two beamsplitters and the rest of the setup stay in the same orientation in the quantum eraser experiment.
- Page 131 Quantum Optics Kit Chapter 10: Additional Experiments Figure 132 Choosing a Working Point in the Interference Signal. Here 9.5 µm is selected. 5. This will be the working point for calibration of the LCCs and later measurements. If the Michelson breadboard changes temperature and expands or contracts, this affects the phase of the interferogram at the working position.
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Page 132: Sample Measurements
Quantum Optics Kit Chapter 10: Additional Experiments Figure 133 Michelson signal with both LCC voltages at 20 V (top) and one LCC voltage at calibrated low voltage (bottom). 10.3.5 Sample Measurements The Deutsch algorithm can now be tested for any of the four possible function inputs: •... -
Page 133: Discussion Of Error Sources
Quantum Optics Kit Chapter 10: Additional Experiments Figure 134 T&B Coincidence Signal for All Four Functions of the Deutsch Algorithm with Voltage Combinations �� �� → �� �� → �� �� → �� �� . The inset shows the Kinesis HIGH HIGH HIGH... -
Page 134: Further Algorithm Ideas
Quantum Optics Kit Chapter 10: Additional Experiments 10.3.7 Further Algorithm Ideas 89,90 Other optical implementations of QC algorithms, such as Grover’s and Shor’s algorithm, can be found in literature. If you have concrete implementations that could usefully extend the scope of this kit, please do not hesitate to contact us. - Page 135 Quantum Optics Kit Chapter 10: Additional Experiments Figure 135 Startup Page of the Time Tagger Software After connecting to your Time Tagger, you will see the “Home” tab with a visual representation of the device and a live view of incoming count rates at the three connected detector inputs. Use the switch above to change to the detailed view, where you can set the input delays (see Figure 136).
- Page 136 Quantum Optics Kit Chapter 10: Additional Experiments Figure 137 Setting Up the Scope in the Time Tagger Software In the “Logic level time trace” tab (see Figure 138), the top graph displays the time trace, as set in the properties panel on the left.
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Page 137: Chapter 11 Software
Settings.xml. This file will automatically be created upon the first start of the software and is located in your documents folder under \Thorlabs\EDU-QOP1. If you wish to have different standard values than the ones supplied, you can either use the respective button in the Configuration tab, see Section 11.9 or change the values in the config file directly. -
Page 138: Alignment Tab
Quantum Optics Kit Chapter 11: Software • Along with the measurement data, the current values of all settings will be saved to a separate .xml file. This file has the same name as the measurement file with an added “_Settings” at the end. •... - Page 139 Quantum Optics Kit Chapter 11: Software Figure 140 Delay Calibration Tab To the left of the graph are the following control elements: • Detector Delay Start / Detector Delay End: Here, the start and end points of the delay offset are set. Detectors A and B are delayed by the specified amount in relation to detector T.
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Page 140: Hbt And Gra Tabs
Quantum Optics Kit Chapter 11: Software 11.6 HBT and GRA Tabs In these tabs, as shown in Figure 141 and Figure 142, the Hanbury-Brown-Twiss experiment and the Grangier- Roger-Aspect experiment, as explained in Sections 3.5.1 and 3.5.3, respectively, can be performed. Both tabs have a similar structure, only differing in the shown quantities. -
Page 141: Malus' Law Tab
Quantum Optics Kit Chapter 11: Software The laser status is displayed below the buttons. The boxes in the right part of the tab contain the measurement results: • The count rates • The absolute count numbers • ( 2 ) ( 0 ) functions for The ��... -
Page 142: Michelson Interferometer Tab
Quantum Optics Kit Chapter 11: Software • Remove Last Point: This button removes the last data point from the plots (e.g., if you accidentally used the wrong angle value). It can be used multiple times to remove more than one point. Please note that removed data points are lost and cannot be restored. -
Page 143: Configuration Tab
Quantum Optics Kit Chapter 11: Software measurement ranges, we recommend the minimum setting of 300 ms. For smaller ranges and if the �� (0) value is of interest, significantly longer times (e.g. 5000 ms) are advantageous. • Stage Start Position / Stage End Position: Here, the start and end point of the measurement are set. •... -
Page 144: Hidden Settings
There are two settings that make more complex changes and are therefore not controllable via the software. Those settings can be changed directly via the config file, which is located in your documents folder under \Thorlabs\EDU-QOP1. The hidden settings are: •... -
Page 145: Chapter 12 Technical Notes
Quantum Optics Kit Chapter 12: Technical Notes Chapter 12 Technical Notes 12.1 Different Detection Schemes 12.1.1 Standard Triple Coincidences When looking at the Time Tagger in this kit and many coincidence electronics in the literature, the standard way to define triple coincidences deviates from the definition used in Section 3.5.4. (from here on called “coincidence of coincidences”... -
Page 146: Gated Detection Scheme
Quantum Optics Kit Chapter 12: Technical Notes ( 0 ) = 1 for uncorrelated light and shows that the standard definition of This deviates from the expectation �� ������ triple coincidence is not perfectly suited for the GRA experiment. ( 0 ) for the CC definition of triple coincidences. The probability for an A stochastic view helps to calculate ��... -
Page 147: Changing The Detection Scheme In The Software
Quantum Optics Kit Chapter 12: Technical Notes The equations for the second order correlation function in the GRA experiment become: (��) �� ∙ �� �� ���� ( 0 ) = �� ������ (��) (��) �� ∙ �� �� �� The time window used for gating ∆�� is the same as the coincidence window ∆��... -
Page 148: Environmental Conditions
Figure 152 Setup with Wavelength Filtering Enclosure Please contact for a part list recommendation and a construction manual for such a Techsupport@thorlabs.com box. 12.3 Avoiding Fluctuations in the Michelson Interferometer The Michelson Interferometer is an extremely sensitive instrument. Slight changes in the parameters can have significant influence on the measured signal. - Page 149 Quantum Optics Kit Chapter 12: Technical Notes Example Measurement Without Housing 10.0 10.5 11.0 11.5 Stage Position (µm) Figure 153 Example Interferogram with Air Current in the Michelson Interferometer This problem can be alleviated by housing the interferometer in a box that prevents air currents from entering the interferometer.
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Page 150: Accidental Coincidences
Quantum Optics Kit Chapter 12: Technical Notes Example Measurement With Housing 10.0 10.5 11.0 11.5 Stage Position (µm) Figure 155 Example Measurement with Interferometer Housing 12.4 Accidental Coincidences In Section 3.5.7, we discussed the influence of the count rate and the coincidence window on the rate of accidental ( 0 ) . - Page 151 Quantum Optics Kit Chapter 12: Technical Notes ( 0 ) measurement’s statistical error, we assume that the error is dominated by the For the calculation of the �� ������ event counting measurements. In turn, the errors of the coincidence window width ∆�� and the measurement duration ��...
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Page 152: Maximizing The Count Rate
Quantum Optics Kit Chapter 12: Technical Notes Constant Trigger Rate (200 kHz) 0.020 Error Region for T = 1 s Error Region for T = 10 s 0.015 0.010 0.005 0.000 Coincidence Window (ns) Figure 157 Expected measurement results as a function of the coincidence window width for a constant trigger count rate of 200 kHz. -
Page 153: Choice Of Polarizers
Quantum Optics Kit Chapter 12: Technical Notes Please be aware that higher count rates are not always beneficial. For a fixed coincidence window, higher count rates result in more accidental coincidences, thus moving the �� (0) closer towards 1, as explained in Section 12.4. -
Page 154: Axicon Design
Quantum Optics Kit Chapter 12: Technical Notes 12.8 Axicon Design The axicon is designed to emulate the cone of photon pairs generated in the BBO crystal. A schematic is shown in Figure 158. Figure 158 Schematic of the Axicon As the BBO is designed for a half opening angle of 3°, the axicon parameters are chosen to produce a cone with an opening angle of 3°... -
Page 155: Movable Michelson Interferometer
Thus, the count rate ratio can be continuously varied. Exercise caution when using this arrangement for polarization sensitive experiments. A suitable wave plate (Item # WPH10ME-808) is part of the kit and Thorlabs offers other suitable beamsplitters such as the CCM5-PBS202(/M) beamsplitter. -
Page 156: Polarization In The Spdc Process
Quantum Optics Kit Chapter 12: Technical Notes • Remove the temporary clamps from the first step. Now the Michelson board can be moved in and out of the measurement position. • In the measurement position, the board should be secured against lateral movement by a fifth clamp which is pressed against the board diagonally to the axes defined by the other clamps. -
Page 157: Chapter 13 Troubleshooting
Section 7.1. In rare cases, the laser diode might have burned out. If you have checked all the above points and the pump laser is not working, please contact Techsupport@thorlabs.com 13.2 Low Count Rates with Filter Problem: In Section 7.4.4, the count rates are much smaller than 300 kHz. -
Page 158: Low Coincidence Count Rates
Quantum Optics Kit Chapter 13: Troubleshooting • Make sure that the laser current is set to a value that corresponds to about 13 mW of output power (compare the spec sheet of your individual laser diode). • Make sure that the crystal is oriented correctly (see Figure 37) •... -
Page 159: Michelson Interferometer Problems
Quantum Optics Kit Chapter 13: Troubleshooting 13.6 Michelson Interferometer Problems If in Section 7.6.6, you see a very low count rate on detector B and/or a very low coincidence count rate T&B: • Move the alignment laser to the magnetic post behind the crystal and use it to check whether all iris apertures and optical elements are correctly positioned (the beam should pass through the center). -
Page 160: Chapter 14 Laser Safety Calculation
Quantum Optics Kit Chapter 14: Laser Safety Calculation Chapter 14 Laser Safety Calculation 14.1 Laser System In this EDU-Kit we are using the L405P20 laser diode. Each institution that uses this educational kit should have a laser safety officer to determine the safety requirements. However, here we give one approach to calculate the risk assessment based on the laser used in this kit. - Page 161 , safety goggles with scale number of D LB4 are required according to the EN207:2017 �� norm (see green field in Figure 163). From the Thorlabs portfolio, the LG3 glasses are therefore a viable choice, as it has a protection level of D LB4 in the relevant wavelength range. Max. Power Density (E, W/m ) &...
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Page 162: Chapter 15 Acknowledgements
Quantum Optics Kit Chapter 15: Acknowledgements Chapter 15 Acknowledgements We are grateful for the various insights we have collected over the years from numerous committed educators who have taken on the challenge of experimentally teaching quantum optics to students. The experimental realization in this kit was heavily influenced by our collaborators from the Leibniz University Hannover. -
Page 163: Chapter 16 Warranty And Rma Information
Waste treatment is your own responsibility. “End of life” units must be returned to Thorlabs or handed to a company specializing in waste recovery. Do not dispose of the unit in a litter bin or at a public waste disposal site. It is the user’s responsibility to delete all private data stored on the device prior to disposal. -
Page 164: Chapter 17 Thorlabs Worldwide Contacts
Quantum Optics Kit Chapter 17: Thorlabs Worldwide Contacts Chapter 17 Thorlabs Worldwide Contacts For technical support or sales inquiries, please visit us at for our most up-to-date www.thorlabs.com/contact contact information. USA, Canada, and South America UK and Ireland Thorlabs, Inc. - Page 166 www.thorlabs.com...
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