Regarding the alignment, I have developed a compensation optics to replace the LPF. It should solve the focus shift issue (pretty much to a level tolerable within a few dozen microns). Kindly let me know if anyone is interested in since I got plenty these optics made.
There are plenty used rare gas lamps, e.g., UVP, Newport. Here is a fixture for these lamps when coming to the spectrometer calibration:
https://www.ebay.com/itm/283131698740?ssPageName=STRK:MESELX:IT&_trksid=p3984.m1555.l2649...
In the pictures,
U16Base is the spectrum from a Kr lamp without touching any optics.
U16-LPF is after removing the LPF.
U05TC is another unit after removing LPF but ended up fairly good in resolution.
I finally have the data to demonstrate the potential issue of removing the filter without alignment. There will be aberration and defcous. I used a PenRay (Kr, Ar, HgNe, etc) lamp to check the spectral line shape and resolutions. Here is one example comparing the before and after removing the...
Did you realign the focusing mirrors (both the input and the one after grating)? I suspect there should be significant degradation in resolution without properly align/compensate the focus. I am getting my spectral calibration lamp setup in a few days. It would be interesting to see the filter's...
Hello! I have been playing with this model and re-designing compensation optics for taking the filter out. I got a bunch them under fabrication. Kindly advise if anyone is interested in using my design.
Sincerely,
Dan