There are lot, depending on your requirements. Anyway you can try: 3agNB F2
5p
)IV>G
1, Refractive: an achromatic as positive + plano-convex as negative; <I1y
OR j{"[Ec
2, Reflective: two parabolic mirrors; L=m:/qQL
2&x7W*
Both of them affer nice spherical aberration performance. ph#efY`a:
8}z3CuM
Reminder: compute the laser beam density, ensure you have enough strong optical coating. lM+ xU;
QT;Va#a
Good luck.