[Erin, Daniel]

We first wanted to find a way to change the polarization of the light in the Shack-Hartman Wavefront Sensor setup so that all of the light going through beam splitter is transmitted. We could do this by rotating the fiber itself (carefully, without straining the fiber). This had a tendency to misalign the lenses and the mirrors when done without changing the setup however, so a much better strategy is to move the beamsplitter so it is right after the fiber collimator, and then rotating the fiber until the beam fully transmits (using the power meter to make sure). Then the beamsplitter can be returned, and any final alignment can be done.

After that, we aligned the quarter wave plate, and added a 775 HR mirror where the end mirror mount would go, just for testing. We also made sure the polarization angle maximized the light output back out of the beamsplitter (see the setup). 

Then we set up the MLA and attached it to the camera using an adapter. We got some really interesting images (see attached) and ended up adding an ND filter to both protect the MLA/camera from a strong beam and to make the images a bit sharper. I took several different images of the 775nm HR mirror at different distances, with different ND filters, and added a lens 300 nm lens after the mirror create the effect of a curved mirror. I am going to use an adaptive optics python library I found and see if the SHWS analysis feature works (if not, there is are a few MATLAB ones that should also work). If neither of these are good, I also took an image without the MLA so I can compare the two to determine how much the array moves the light. I also want to see if it is necessary to image the entire set of all 300 mircolenses, or if only a region is sufficent, and if the MLA needs to be rotated, or if I can just rotate the image. 

We also finished assembling the end mirror mount (see attached) and we added the parts that allow us to adjust the pressure on the mirror itself. I plan to start imaging the uncoated silicon mirror tomorrow as well using the MLA. 

I also made sure our setup collimates the beam using Ian's gaussian beam fit code and while the beam isn't exactly symmetric, the waists are extremely consistent across several different distances (see the attached graph). This is a good sign, since it means we can image a 6mm diameter center of the silicon mirror consistently.