There are lot, depending on your requirements. Anyway you can try: d/b\:[B@ zhe~kI 1, Refractive: an achromatic as positive + plano-convex as negative; JF'<"" OR [M#(su0fv 2, Reflective: two parabolic mirrors; f jMmlp / <+F/R'=O Both of them affer nice spherical aberration performance. oz%{D@CF 4WPco"xH! Reminder: compute the laser beam density, ensure you have enough strong optical coating. z2jS(N?J1 SB:z[kfz| Good luck.
Hi, Mn*5oH =%{E^z>1 The following is a link of technical data of optical adhesives, hope it be helpful: X=VaBy4# BPu>_$C http://www.lienhe.com.cn/uvadh/NOA60.htm +$R%Vbd GPAz#0p Double check from your lens vendor waht type of adhesive they use for your cemented doublet. w!R J8 2\#~%D>[ 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. _:Ov-HIR zeuSk|O Again, good luck.