There are lot, depending on your requirements. Anyway you can try: D@j `'&G +F0M?, 1, Refractive: an achromatic as positive + plano-convex as negative; s}HTxY; OR }D|"$* 2, Reflective: two parabolic mirrors; Fir7z nRW &_-~kU1K^ Both of them affer nice spherical aberration performance. v=X\@27= ? % l5J Reminder: compute the laser beam density, ensure you have enough strong optical coating. 52%.^/ (nV/-#* Good luck.
Hi, #%E~IA% y|1-,u.$ The following is a link of technical data of optical adhesives, hope it be helpful: 30B!hj$C 3 i>uKU1 http://www.lienhe.com.cn/uvadh/NOA60.htm CaK 0o*D R2r0'Yx Double check from your lens vendor waht type of adhesive they use for your cemented doublet. G:A`
n;E0 -1U]@s It is OK to use the spaced doublet design as a backup, if so, please pay a lot attention on the opto-mechanical design and assembling. /dtFB5Z"w .+ _x|?' Again, good luck.