Laser beam expander: 5X

Claim 2

A lens system operative at a common focal position over a wavelength range from 0.365 micron to 1.3 micron for expanding an optical beam by five times in diameter, said lens system comprising a plurality of lens elements, all of said lens elements being made of optical glass, said lens elements remaining at fixed positions with respect to each other for operation of said lens system over said wavelength range, said lens system being substantially diffraction limited over said wavelength range.

Claim 3

The lens system of claim 1 consisting of four lens elements made of optical glasses.

Claim 4

A laser beam expander comprising four lens elements configured and positioned with respect to each other along an optic axis according to a design form specified as follows: ______________________________________ Surface Radius Thickness No. (mm) (mm) N.sub.d V.sub.d Material ______________________________________ 1 -5.8219 2.0000 1.788310 47.394 LAF21 2 -10.1785 67.7952 Air 3 -180.8825 3.0000 1.788310 47.394 LAF21 4 47.5947 0.5200 Air 5 40.6509 2.0000 1.698951 30.067 SF15 6 50.2010 0.2540 Air 7 99.8816 3.9700 1.528554 76.960 PK51 8 -25.5475 10.0000 Air ______________________________________ where the surfaces of the lens elements are numbered consecutively from left to right along the optic axis, and where N d is the index of refraction at the wavelength of the sodium d spectral line and V d is the Abbe number at the same wavelength.

Claim 5

A laser beam expander comprising four lens elements configured and positioned with respect to each other along an optic axis according to a design form specified as follows: ______________________________________ Surface Radius Thickness No. (mm) (mm) N.sub.d V.sub.d Material ______________________________________ 1 -5.8219 2.0000 1.788310 47.394 LAF21 2 -10.1785 67.7952 Air 3 -180.8825 3.0000 1.788310 47.394 LAF21 4 47.5947 0.5200 Air 5 40.6509 2.0000 1.698951 30.067 SF15 6 50.2010 0.2540 Air 7 99.8816 3.9700 1.528554 76.960 PK51 8 -25.5475 10.0000 Air ______________________________________ where the surfaces of the lens elements are numbered consecutively from left to right along the optic axis, and where N d is the index of refraction at the wavelength of the sodium d spectral line and V d is the Abbe number at the same wavelength.