Optical Trap Kit Components - THORLABS OTKB Manual

Optical Trapping Kit OTKB(OTKB/M) Components
Part 4.
This section provides some technical details on the individual components used to build this system.
Like many optical trapping systems, this one is based on an inverted
microscope design. The structure of the inverted light microscope is
constructed using Thorlabs‟ 60mm cage system, which is supported by a
damped 1.5" post (Item # DP14). All of the parts discussed in this
section are included in the OTKB kit unless otherwise noted. Some of the
parts mentioned below are not universal so the metric version of the part
is used in the OTKB/M kit.
1) The 975 nm trapping laser source is a pigtailed Fiber Bragg
Grating (FBG) stabilized single mode laser diode in a
hermetically sealed 14-pin butterfly package. The integrated TEC
element and thermistor in the butterfly package allow the
temperature of the laser to be precisely controlled when mounted
in the LM14S2 laser diode mount and controlled using an
LDC210C laser diode current driver and a TED200C temperature
controller. This laser, mount, and controller combination was chosen to ensure that the output
power (330 mW max) of the laser will be extremely stable, which is important to maintaining a
constant trapping force.
2) The FiberPort (Item # PAF-X-7-B) collimates the output of the trapping laser. The FiberPort is a
versatile collimator since it allows the aspheric collimation lens to be precisely positioned with 5
degrees of freedom (X, Y, Z, Pitch, and Yaw). For polarization sensitive applications, the
keyway on the FiberPort can be rotated about the optical axis so that the orientation of a linearly
polarized collimated beam can be set.
3) The two achromatic doublet lens pairs ACN254-050-B and AC254-150-B expand the collimated
trapping laser beam by a factor of 3.
4) The dichroic mirror that is mounted in the central C6W reflects 980 nm light (trapping source)
while passing visible light.
5) Visible light from the LED light source illuminates the sample and is then imaged on the 1280 x
1024 pixel color CCD camera (Item # DCU224C) using an achromatic doublet AC254-200-A.
The dichroic mirror in the light path in combination with a short pass filter prevents
backscattered light from the 980 nm laser from saturating the CCD detector.
6) A 100X oil immersion Nikon objective lens (Item # OTKOBJ) is used to focus the 980 nm laser
beam down to form the optical trap. The calculated diffraction limited trap diameter is 1.1µm. A
10X Nikon objective is used as the condenser (Item # OTKCON) and collimates the beam after
the optical trap.
19590-D04-V15; Apr 12, 2012 Page 8
Optical Trap Kit
1
LDC210C
TED200C
LM14S2
Figure 3.1: Pigtail laser, mount
and controllers
www.thorlabs.com
C