THORLABS OTKB/M User Manual page 10

Modular Optical Tweezers Chapter 5: System Setup
Step 2: Beam Expander Segment (OTKB-2)
Mount the beam expander segment onto your optical table or breadboard. Six small clamps (Thorlabs item number
CL6) will be used to clamp the segment down onto the table. Only tighten the screws at the laser port for now.
Remove the caps which were used as protection during shipment. Connect the laser collimator/adapter built in step
1 to the laser port. Connect the patch cord coming from the laser controller.
Trap Port
Camera
Port
Mirror 2
Laser
Port
Mirror 1
Figure 4 Left: Beam expander segment. Right: Collimator and patch cord connected to beam expander
segment.
Open the beam expander segment by loosening the two set screws on the cage plate mirror 1, see Figure 4.
Remove the lens tube assembly so that the beam is accessible after Mirror 1. Temporarily move the cage rod
connected to the top of the laser safety cylinder, so that you can put the cage alignment plate (Thorlabs item number
VRC4CPT) in place which is included in the laser segment as shown in Figure 5. Turn the laser on and use the
adjusters on the right angle mirror mount to center the beam. The laser current can be set to around 100 mA for
these alignment steps. Follow all laser safety regulations.
Figure 5 Beam expander segment opened to align first mirror.
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