There are lot, depending on your requirements. Anyway you can try: urB3
0cUt"(]
1, Refractive: an achromatic as positive + plano-convex as negative; ;LE
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OR -JENY|6
2, Reflective: two parabolic mirrors; o?FUVK
wcf_5T
Both of them affer nice spherical aberration performance. EvmmQ
TMCA?r%Y\
Reminder: compute the laser beam density, ensure you have enough strong optical coating. uCfp+
~Wm}M
Good luck.