There are lot, depending on your requirements. Anyway you can try: SK
R1E];4
0<.RA%dj
1, Refractive: an achromatic as positive + plano-convex as negative; x2W#ROfg
OR A@$kLex
2, Reflective: two parabolic mirrors; HBiBv-=,
u9Y3?j,oC
Both of them affer nice spherical aberration performance. !SxG(*u
fS=hpL6]@
Reminder: compute the laser beam density, ensure you have enough strong optical coating. `A)"%~
h|)vv4-d|
Good luck.