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Femtochrome FR-103MN Instruction Manual

Rapid scanning autocorrelator
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FEMTOCHROME. RESEARCH, INC.
FR-103MN AUTOCORRELATOR
INSTRUCTION MANUAL

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  • Page 1 FEMTOCHROME. RESEARCH, INC. FR-103MN AUTOCORRELATOR INSTRUCTION MANUAL...
  • Page 2 2123 4th Street Berkeley, California 94710 Tel (510) 644-1869 Fax (510) 644-0118 r^r\m / fom tnr^hrnm A r.n m o n n n il* to ^ h (3 )fo n n tn ^ h r r % n n o h t t r v /...
  • Page 3 TABLE OF CONTENTS L Introduction..........2. Theory of Operation........3. Operating Instructions a. Fundamental Characteristics... b- Alignment Procedure...... a Alignment H ints......cL Wavelength Dependence....e. Wide Scan Range/Scan Nonlinearity f- Input Beam Polarization ....g. Pulsewidth Calibration ....h.
  • Page 4 Options a. Crosscorrelation (/CC).......... b. Interferometric Option (flO) ...... c. Fiber Adapter (/FA)..........d Fiber Coupled (/FC)..........e- Low Rep Rate Option (/LRR)........ f. Computer Data Acquisition (/CDA) ..g- VGA Display Option (/VGA) ......h- Extended Wavelength (IR) Options (/1000, /2000) Spare Parts L ist............
  • Page 5 An optional A/D board installed in the unit and its software (Computer Data Acquisition (/CDA))， provides an interface (RS232) of the FR-103MN with a PC, resulting in a complete pulsewidth monitoring system. Alternatively， the N GA option renders the unit completely self-contained in a single package including a color TFT display.
  • Page 6 The operation ranges of the FR-103MN can be interchangeably selected as follows1 : FR-103MN/BBO (410-900 nm): BBO crystal (0.3 mm/60°)/VS Beamsplitter/VS PMT...
  • Page 7 2. THEORY OF OPERATION The FR-103MN utilizes the SHG method of the 1st kind in the conventional Michel son Interferometer set-up of pulsewidth measurement.5 In the standard configuration, noncollinear beams lead to the background-free autocorrelation measurement Repetitive linear delay generation in one arm of the Michelson arrangement is introduced by a pair of parallel (//) mirrors centered about a rotating axis.6 In the geometry of Figure 1，...
  • Page 8 A figure of nonlinearity over the full scan range is6 NL=d/4D In the standard configuration of the FR-103MN， the scan mirror has a size of d = 0.75n and the mirrors are separated by a distance of D = 1.25”. The rotation frequency is f = 10 Hz. [f=5Hz .
  • Page 9 Pos.#0. In Pos.#l & 2 the trigger DELAY is functional* Notes: 1 • In the factory setting of the FR-103MN， the TRIG SELECT switch is set to “0 and the autocorrelation trace peak occurs right at the (+) edge of the DELAY disabled trigger pulse，...
  • Page 10 The basic properties of the FR-103MN can be summarized as follows: Scan Range: >7 5 psec Resolution9: <5 fsec Delay Calibration Factor (T/t): 12.5 psec/msec( 10Hz). The exact value of this factor has a weak dependence on the position of the pulse peak within the delay window (scan range).
  • Page 11 3b. Alignment Procedure The standard optical schematic of the FR-103MN is sketched in Figures 2 and 3. [When /FA(CC) Option is included, the alternate beam configuration described in section 4.a is applied. In this case, the delayed and fixed beams described below are reversed. See Sect.4a] The beams lie mainly in the horizontal plane through the centers of Ml and the input...
  • Page 12 (i) Direct the vertically polarized input beam through the center of the input aperture and orient the FR-103 (by lateral movement and/or using the level adjustment knobs) such that the incoming beam is incident on Ml slightly left of center (looking from the front side). The return beam from the comer mirror will form a spot on Ml symmetrically displaced to the right by 6-7 mm.
  • Page 13 (iv) Alignment of M2 is controlled by three fine adjustment screws. Two of these, orthogonally about the central one， render vertical and horizontal tilts. The central screw causes mirror translation and thereby focus adjustment. The factory set controls of M2 should not need to be readjusted.
  • Page 14 (viii) The SHG crystals are generally hygroscopic. For maximum resolution， the crystals are provided without windows but with single layer MgF2 AR coatings which yield good protection against exposure to H20. A desiccator is also provided as a cover， for long term reliability of the NL crystal.
  • Page 15 3e. Wide Scan Range/Scan Nonlinearity The delay range of the FR-103MN is proportional to the mirror size used in the // mirror assembly. For long pulsewidths, the effect of scan nonlinearity needs to be taken into account The pulse delay，...
  • Page 16 3g. Pulsewidth Calibration Calibration of the FR-103 can be determined by translation of the micrometer driven retroreflector stage in the stationary aniL For a given translation x， the corresponding shift s in the position of the trace peak (Figure 8) yields the calibration factor using the conversion formula ⑶...
  • Page 17 3h. Major Optics Alignment Realignment of the pellicle beamsplitter (PBS) and the fold mirror Ml may be necessary if either component has been moved. Fold Mirror (M l) Alignment Direct the input beam， using the level adjustment knobs and/or lateral movement of the FR-103, such that it is incident on Ml slightly to the left of center as depicted in Figure 4.
  • Page 18 4.0PTI0NS 4a« Crosscorrelation The FR-103MN can readily be used to crosscorrelate ultrashort pulses from two separate beams* The second beam for crosscorrelation (CC) is introduced thru， the center of the opening in the right side plate.( A fiber adapter [/FA(CC)] can be installed at this port, also.)
  • Page 19 5. Set the integration time constant switch to 1 fsec, and the motor speed to lowest (2JHz). 6. Fringe resolved autocorrelation will now be observed， when the retroreflecting mirror on the // mirrors side is properly aligned using the control knobs on the Right Side Panel, 7.
  • Page 20 4b. Interferometric Option (/IO) 1.The FR-103 is aligned for the standard noncollinear (background free autocorrelation) operation, with the retroreflecting comer mirror in its proper position on the translation stage. 2.The comer-mirror is then removed and the Interferometric Option is mounted on the T-stage, 广...
  • Page 21 4c. Fiber Adapter(/FA) A single mode fiber coupled beam can be input to the FR-103 by means of the Fiber Adapter* A broadband AR coated single aspheric lens provides beam collimation. Housed in a mirror mount， the adapter/lens assembly is aligned through horizontal and vertical tilt controls. Once aligned，...
  • Page 22 4e. Low Rep Rate Option (/LRR) The /LRR option renders the FR-103 to be operable with any pulse repetition rate (>4Hz). Whereas autocorrelation traces can be directly displayed on an analog scope for high pulse rep rates (>200kHz)， for lower rep rates，the autocorrelation traces can be directly accumulated and displayed on a digital oscilloscope with persistence set to utilizing the /LRR option- Introduction...
  • Page 23 Note that the rotation rate of the motor (fr) is to be fr = 4/(+) 4. Apply trigger pulses (+going w/4,12Volts amplitude， + edge synchronized with the laser pulses within |nsec)， to the REF IN BNC on the back Panel. The FR-103 should be turned ON， before 士...
  • Page 24 4f. Computer Data Acquisition (/CDA) Option Introduction The Computer Data Acquisition (CDA) option allows the FR-103 Auto/Crosscorrelator to be connected to a PC via the RS232 serial port The accompanying software provides ‘real-time’ monitoring and characterization of the pulses. Data is collected for the current pulse profile， the average of the accumulated data, and the envelope data [when /LRR is being used，...
  • Page 25 With the autocorrelator turned ON and connected to the PC， begin data acquisition by typing: at the DOS prompt If the directory containing the Femtochrome files is not included in your DOS path variable, you must be in the directory containing the MN.EXE program (C:\CDA ) ，...
  • Page 26 (P) Print screen By pressing "P"， the current data displayed on the screen at that instant will be 聽 printed* The printing process will briefly interrupt data acquisition. NOTE: The DOS GRAPHICS printer driver must be loaded for this option to work properly. See "Set Up"...
  • Page 27 In the envelope data window， there are four new menu options: (T) Avg Envelope By pressing “T”， the accumulated average of envelope data traces (each 嶋 being collected over #acq scans) is plotted- (N) ReNew Envelope - By pressing C € N’' the envelope trace is refreshed after a new one is collected (#acq scans).
  • Page 28 4g. VGA Display Option(/VGA) An embedded PC is installed in the FR-103, and an LCD display and keyboard are incorporated on the unit. The operation with this option follows /CDA, and starts with the command C:\>MN. The data which has been saved can be transferred to another PC, using the application FT.exe. [Command C:\>FT.] The contents of the floppy disk accompanying this option [RC.exe]needs to have been installed into the PC to be used for this purpose.
  • Page 29 5. SPARE PARTS LIST The following is a parts list for the major components of the FR-103MN Optical Components Description Femtochrome Part # 103MN-001 // Mirror Assembly 103MN-002 Pellicle Beamsplitter (specify VS/IR) 103MN-003 Folding Mirror (Ml) 103MN-004 Focusing Mirror (M2)
  • Page 30 ， Femtochrome shall in no way be liable for damages consequential or incidental to defects in any of the products， for injuries resulting from its use, or for any other cause. This limited warranty constitutes the full understanding of Femtochrome and the buyer， and no...

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