MOUNTING MODULES ON THE VERTICAL BREADBOARD
SECTION 3: WIRING
Set up scanimage
Machine data file setting
Wiring galvos / voice coil / PMTs / etc.
SECTION 4: TABLE OPTICS ALIGNMENT
Align table optics at 900nm with the laser in alignment mode
1) Mount pockels cell just after laser, and align so that beam goes through it. Then manually set pockels cell power to about 10% for the rest of the alignment procedure.
2) Place beam expander after pockels cell. Adjust its height and the position of the front entrance such that the beam passes through the center of the iris on the beam expander. Adjust the position of the back end of the beam expander such that the beam passes straight through it. Adjust the beam expander so that the beam is collimated.
3) Position two silver mirrors such that the beam hits their centers and is steered towards the PPC. Make sure the beam remains level at its original height. Do this using an IR card stuck to a support to check beam height at different positions.
4) Place the uniblitz shutter just before the PPC in the path of the beam.
5) Adjust the positions of the enterance and exit irises at the beginning and end of the PPC so that the beam passes centeres through them.
6) Adjust height and lateral position of first two mirrors such that the beam hits both of them in the center. Then adjust the orientation of the mirrors so that the exiting beam direction is normal to entrance beam.
7) Position the large silver mirror such that the beam is centered on it, and adjust the mirror position such that the reflected beam is parallel to table and then adjust its angle it is entering prism close to its far edge.
8) Now adjust angle of prism to find the angle of minimum deviation using rotation stage (coarse). Do this by placing an IR card far away and rotating prism to find angle where beam is furthers to the right.
9) Now make sure reflected beam and incident beam are coplanar by adjusting the angle of the prism and looking at the height of the reflected beam on the IR card. The reflection is very faint and needs an IR viewer to be seen.
10) Now make sure the refracted beam is coplanar with the reflected and incident beam by adjusting the other angle of the prism.
11) Redo finding angle of minimum deviation using fine adjustment. This will be the angle where the beam is the rightmost possible.
12) Algin retroreflector axis. Adjust height of retreflector such that the return beam is centered on the roof mirror. Then adjust close side of rail such that the returning beam is hitting the prism a little further into the prism (2 to 3 mm). Then adjust the back position such the rail is exactly parallel to the beam. Slide the retroreflector back and forth along the rail to check that it is moving along the axis of the beam.
13) Adjust lateral position of roof prisms so that return beam is entering the prism, and rotate it so that the outbound beam 3 is hitting the retroreflector. Do fine angle adjustments of the prisms angle such that return beam 4 is level to table and colinear with track.
14) Mount output coupler. Place in bypass mode, and set target card after exit iris. Left bypass mode. Align exit beam to pass through iris and hit target by adjusting height of retroreflector so that beam passes through center of exit iris and move mirror to translate mirror, and use angle of mirror to make beam hit target on iris card.
15) Add two mirrors such that beam is level as it goes into the entrance of periscope.
16) Set periscope entrance mirror center to be 120 mm heigh (height of laser beam).
Pockels cell
Shutter
2x table beam expander
Assembling the compressor
Build enclosure for table optics
SECTION 5: MICROSCOPE ALIGNMENT
Multistage periscope alignment
Quarter wave plate adjustment for multistage periscope
Alignment of beam to remote focus objective
Adjustment of quarter wave plates for maximum transmission
Alignment of RF mirror assembly
Alignment of beam to imaging objective using compensators
Adjustment of galvo voltage divider gain
SECTION 6: IMAGING
Dye pool imaging to set compensators
Dye pool imaging to set retroreflector position
Image beads and measure PSF
APPENDIX A:
Accessory optical path
Assembly, alignment, calibration, adjustment
General description: The accessory optical systems of the 2p-RAM couple through a 52 x 72 x 1 mm dichroic/mirror that is placed in the 2p-RAM detection path. This optic can be moved in and out of the optical path with a motor. Its size does NOT support the full FOV and NA of the 2p-RAM imaging or detection paths, but the full FOV is supported at a reduced NA. All light to/from the accessory optical systems goes through the 2p-RAM primary dichroic, so must have a wavelength shorter than the prim dichro cutoff (currently ~720nm) for efficient transmission. The main 2p-RAM tube lens is not part of the accessory optical systems path, so an accessory tube lens is used. All accessory optical systems are light-tight, so little ambient light will enter the 2p-RAM detection path.
The following functionality is implemented:
- Scanning 1p photostimulation system (S1PS): The S1PS roughly images the face of an SMA-terminated optical fiber onto the sample, with a magnification of 1.85x. It supports a fiber NA of up to 0.22 without vignetting. A galvo-galvo scan mirror pair dedicated to this system can scan the fiber-face image anywhere within the 2p-RAM 5mm FOV. It is intended to be used with multimode fibers, such that the spot size at the sample can be changed by changing the fiber core diameter. No light source or fiber is provided. A manual, quick-change filter mount holds a dichroic mirror that couples the S1PS system with the wide-field imaging system, which can be used simultaneously, if their wavelengths are separable.
- Wide-field imaging system (WFIS): The WFIS images the sample onto a CCD camera, with epi-illumination. A quick-change filter cube couples the epi-illumination and imaging, allowing switching between epi-fluorescence imaging and polarization- or absorption-based imaging using a polarizing/non-polarizing beamsplitter cube (some scattering off of this cube from the epi-illumination is visible in the image obtained in the non-fluorescence mode). The epi-illumination module accepts light from a 3mm core diameter liquid light-guide (LLG face is imaged onto objective pupil; NA .24 accepted from LLG; field stop is provided). The imaging goes through a 35mm fixed focal length imaging lens, providing an aperture stop. As configured, FOV at the sample is 4.8 x 6mm, magnification is 1.13x onto the camera, and resolution should be limited by pixel size (5.3 um; 1024 x 1280).
- Coverglass alignment system (CAS): The CAS provides real-time measurement of the angle of the sample coverglass relative to the 2p-RAM objective lens. A 100um pinhole is illuminated by an LED, and then imaged onto the 2p-RAM objective pupil, producing a nearly collimated beam at the sample (beam width is controlled by a variable iris placed next to LED). If no immersion water is used, then the reflected beam from the top coverglass surface is focused onto a camera through a 50:50 beamsplitter. The spot position on the camera gives the coverglass angle, with resolution exceeding 0.1 degree. The CAS is coupled to the S1PS and WFIS with a motorized flip-mirror. The CAS needs to be calibrated for zero-angle. The design for a jig for this calibration, which precisely holds a piece of glass relative to the 2p-RAM objective, will be provided.