There are lot, depending on your requirements. Anyway you can try: '9XSz?
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1, Refractive: an achromatic as positive + plano-convex as negative; ZWXA%u7V
OR |!hN!j*)
2, Reflective: two parabolic mirrors; *c>B,
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Both of them affer nice spherical aberration performance. 1)v]<Ga~%1
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Reminder: compute the laser beam density, ensure you have enough strong optical coating. &3CC |
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Good luck.