There are lot, depending on your requirements. Anyway you can try: I Dohv[#
3Z!% td5n
1, Refractive: an achromatic as positive + plano-convex as negative; ?Nos;_/
OR sy: xA w
2, Reflective: two parabolic mirrors; nBh+UT}
Q_5 l.M/9]
Both of them affer nice spherical aberration performance. z$~x 2<
]I?.1X5d0
Reminder: compute the laser beam density, ensure you have enough strong optical coating. )GD7 rsC`<
%~u]|q<{
Good luck.
