There are lot, depending on your requirements. Anyway you can try: =GXu 5 8 x{&w?ng 1, Refractive: an achromatic as positive + plano-convex as negative; @EoZI~
OR @;?T~^nGj 2, Reflective: two parabolic mirrors; ;zdxs'hJ )=DGdIEt Both of them affer nice spherical aberration performance. =-o'gL EbZdas!l Reminder: compute the laser beam density, ensure you have enough strong optical coating. wI5Yn
h A4QcQ" Good luck.
Hi, {5|("0[F gip/(/NX The following is a link of technical data of optical adhesives, hope it be helpful: |7@O($ b xE-7P|2 http://www.lienhe.com.cn/uvadh/NOA60.htm *{o UWt ^JR;epVJ
Double check from your lens vendor waht type of adhesive they use for your cemented doublet. tMj1~
R pA4*bO+ 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. M=]5WZO~A KTEZ4K^o= Again, good luck.