There are lot, depending on your requirements. Anyway you can try: ;]<{ <czc
)]2yTG[
1, Refractive: an achromatic as positive + plano-convex as negative; 5- Q`v/w;
OR Q
! 5P
2, Reflective: two parabolic mirrors; @Yua%n6]#D
}K=T B}yY
Both of them affer nice spherical aberration performance. /Cd`h ;#@
xN t
Reminder: compute the laser beam density, ensure you have enough strong optical coating. *b" ( r|Ko
cK.T=7T
Good luck.
