There are lot, depending on your requirements. Anyway you can try: @Kri)U
i
g;(r@>U.r
1, Refractive: an achromatic as positive + plano-convex as negative; v | /IN
OR fTi,S)F'
2, Reflective: two parabolic mirrors; g0.D36
\K 01F
Both of them affer nice spherical aberration performance. @URLFMFi
S EY
Reminder: compute the laser beam density, ensure you have enough strong optical coating. ki6`d?
an3HKfv
Good luck.