There are lot, depending on your requirements. Anyway you can try: =&_Y=>rA]0
\!51I./Q/
1, Refractive: an achromatic as positive + plano-convex as negative; 0Z.X;1=
OR -`f 1l8LD2
2, Reflective: two parabolic mirrors; s%bm1$}
b] EC+.
Both of them affer nice spherical aberration performance. ' ?4\
-XJXl}M.
Reminder: compute the laser beam density, ensure you have enough strong optical coating. No\3kRB4bi
n<)gS7
Good luck.