There are lot, depending on your requirements. Anyway you can try: (&,R1dLo
`uHpj`EU
1, Refractive: an achromatic as positive + plano-convex as negative; +kL(lBv'
OR ?xZmm%JF
2, Reflective: two parabolic mirrors; sBnPS[Oo
G65N:
Both of them affer nice spherical aberration performance. Gu).*cU
}HorR2(`N
Reminder: compute the laser beam density, ensure you have enough strong optical coating. 2\de |'
.<%M8rcj
Good luck.