These 0.5 NA cylindrical microlenses are obtained by drawing the fiber-optic preform with radial refractive-index distribution and specific Luneburg type profile into smaller diameter rods.
Rod lenses are highly polished cylinders made of optically transparent and homogeneous materials. Cut-rod cylindrical lenses are derivatives of the mother rod lens obtained by grinding off top and bottom of the rod. The length of rod and cut-rod lenses is diced to required length.
When full angle fast axis beam divergence of laser diode exceeds 60 degrees, the best collimating lens type is high refractive index acylindrical plano-convex lens.
Double-convex lenses have one or two acylindrical surfaces. They are often made of fused silica or lower refractive index glasses.
The FAR lens first collimates fast-axis divergence of a laser diode with a convex surface and then with a concave cylindrical surface reduces the fast axis beam divergence to match that of the slow axis.