There are lot, depending on your requirements. Anyway you can try: U~zy;MT
t08[3Q&
1, Refractive: an achromatic as positive + plano-convex as negative; ^6CPC@B1
OR eq2LV=d{m
2, Reflective: two parabolic mirrors; c~\^C_
kMa|V0
Both of them affer nice spherical aberration performance. 9(a*0H
ady
SwB
Reminder: compute the laser beam density, ensure you have enough strong optical coating. sG|,#XQ
$S/WAw,/
Good luck.