Slab laser system with means to overcome the positive lens effect caused by the thermal gradient in the laser rod

Claim 2

A laser system comprising an elongated slab of laser material having an axis of symmetry extending parallel to the longitudinal dimensions thereof, means to irradiate said slab with pump light through the larger sidewalls thereof, a reflector positioned opposite one end face of said slab to reflect laser rays travelling through said slab parallel to said axis back into said slab, and ray shifting means positioned opposite the other end face of said slab to reflect laser rays travelling through said slab parallel to said axis back into said slab and to shift the rays which are near the center of said slab to be near the sidewalls of said slab and vice versa.

Claim 3

A laser system as recited in claim 1 wherein said ray shifting means shifts each ray so that after being shifted such ray is the same distance from a larger sidewall of said slab that such ray prior to being shifted was from a center plane passing through the middle of said slab parallel to said larger sidewalls.

Claim 4

A laser system as recited in claim 1 wherein said ray shifting means shifts the rays from one side of said slab to the other, said sides of said slab being divided by a center plane passing through the middle of said slab parallel to said larger sidewalls.

Claim 5

A laser system as recited in claim 3 wherein said ray shifting means comprises a second reflector facing said other end face of said slab, a calcite plate between said reflector and said slab oriented to laterally shift rays which are polarized so that their E vectors are perpendicular to said center plane, first polarization rotating means to rotate 90* the polarization of laser rays travelling parallel to said axis between said center plane and the plane of one of said larger sidewalls as such laser rays travel between said calcite plate and said other end face of said slab, and second polarization rotating means to rotate 90* the polarization of lazer rays travelling parallel to said axis between said center plane and the plane of the other sidewall of said slab as such rays travel from said calcite plate to said second reflector and back.

Claim 6

A laser system as recited in claim 4 wherein said calcite plate laterally shifts the rays by an amount equal to half the thickness of said slab.

Claim 7

A laser system as recited in claim 4 wherein said first polarization rotating means comprises a hAlf wave plate positioned between said calcite plate and said other end face of said slab and extending only from said center plane to the plane of one of said sidewalls, and wherein said second polarization rotating means comprises a quarter wave plate positioned between said calcite plate and said second reflector.

Claim 8

A laser system as recited in claim 4 wherein said second reflector is parallel to said end face and is co-extensive only with the half of said end face between said center plane and the plane of said other sidewall.

Claim 9

A laser system as recited in claim 1 wherein said laser material is laser glass.

Claim 10

A laser system as recited in claim 1 including means to polarize the laser oscillations generated by said system to have their E vectors to be parallel to said larger sidewalls.

Claim 11

A laser system comprising an elongated block of laser material having an axis of symmetry extending parallel to the longitudinal dimension thereof, means to pump said laser material in a manner to generate an approximately one dimensional thermal gradient in said block with the locus of high temperature being on a plane passing through the middle of said block parallel to a pair of sidewalls of said block, a reflector positioned opposite an end face of said block to reflect laser rays travelling through said block parallel to said axis back into said block, and ray shifting means opposite the other end face of said block to reflect the rays travelling through said block parallel to said axis back into said block and to laterally shift the rays near said center plane to be near said sidewalls and vice versa.

Claim 12

A laser system comprising an elongated block of laser material having an axis of symmetry extending parallel to the longitudinal dimension thereof, means to pump said laser material in a manner to generate an approximately one dimensional thermal gradient in said block with the locus of high temperature being on a plane passing through the middle of said block parallel to a pair of sidewalls of said block, a reflector positioned opposite an end face of said block to reflect laser rays travelling through said block parallel to said axis back into said block, and ray shifting means opposite the other end face of said block to reflect the rays travelling through said block parallel to said axis back into said block and to laterally shift the rays near said center plane to be near said sidewalls and vice versa.

Claim 13

A laser system as recited in claim 10 wherein said laser material is laser glass.

Claim 14

A laser system as recited in claim 10 wherein said ray shifting means shifts the rays laterally in a manner so that the distance that each ray is from the center plane before being shifted is equal to the distance that such ray is from a sidewall of said block after such ray has been shifted.

Claim 15

A laser system comprising an elongated slab of laser material, means to excite said laser material, reflector means defining a laser cavity running through said slab parallel to the longitudinal dimension of said slab whereby laser oscillations are generated in said cavity through said slab, and means to polarize said laser oscillations so that their E vectors in said slab are parallel to the larger sidewalls of said slab.

Claim 16

A laser system comprising an elongated slab of laser material, means to excite said laser material, reflector means defining a laser cavity running through said slab parallel to the longitudinal dimension of said slab whereby laser oscillations are generated in said cavity through said slab, and means to polarize said laser oscillations so that their E vectors in said slab are parallel to the larger sidewalls of said slab.

Claim 17

A laser system as recited in claim 13 wherein said laser material is laser glass.