Julian’s Test Page

I am thrilled to see your work on a new kind of microscope that is reflective multi immersion microscope which is relatively simpler to develop in laboratory environment. However, a question remains in my mind- how did you tune the correction plate everytime when you play with different medium between the mirror and the plate. Could you please elaborate me a bit on this part?

Thanks a lot for writing this article! It triggered a lot of thinking on my part to improve some of our alignment procedures. I’ve built the same autocollimator and have been testing it out for aligning a microscope objective/tube lens/4f system. Here’s a summary of what I have l learned: 1. The autocollimator is really good for axial lens positioning. In my opinion it’s even better than a shear plate. However, it doesn’t help much for the other four degrees of freedom (x, y, tip, tilt) and this matters if you don’t use a cage system or have very tight tolerances that you need to follow on these DOFs. To align these DOFs, you can put a beam splitter immediately after the autocollimator’s 2″ lens with an iris in between, then couple in an alignment laser. (I use the collimated output from a single mode fiber.) I tune the mirror and laser so that the laser is backreflected on itself, then roughly position the autocollimator so that the beam is aligned to it as well. This makes the laser’s path the reference axis, and the goal will be to place all lens surface centers of curvature onto this axis. You can then use laser back reflections and check for forward beam deviations to align lens x, y, tip, and tilt, and then switch to the autocollimator to align the axial position. Iterate until all five DOFs of a lens are aligned. 2. It’s possible to leave the autocollimator and mirror in place when adding all the components (except the camera, see below) without moving it after adding a lens. However, it will be more difficult to find the “x” for every second lens added. This is because the primary image of the reticle is retroreflected if you have an odd number of lenses between the mirror and autocollimator. In retroreflection, a point is imaged onto itself regardless of misalignments of the mirror or lenses. However, for an even number of lenses, the primary image is autocollimated, which means its position is sensitive to misalignment. 3. You can use the autocollimator to place a camera in the focal plane of the lens by moving the autocollimator to the front side of the tube lens/4f system and using the protective glass coating on the camera chip as a parital mirror. You can use the autocollimator’s camera, the camera under alignment, or both to view the “x” and position the camera until both x’s are in focus. 4. I recommend inserting the optics in this order: tube lens, first Fourier lens, second Fourier lens, camera (only x, y, tip, and tilt), objective. I’m still working out the details of the objective and camera alignment, but I rely heavily on the fact that infinity correcteb objectives/tube lens combos are not afocal and thus don’t need precise relative axial positioning. Thanks again!