Patent ID: 8274743

Claim:
A method for thermally compensating lenses in an optical system for high power lasers, comprising the steps of: providing a high power laser, said high power laser emitting a high power laser beam that caused heat-induced changes in an index of refraction of a lens through which said high power laser beam passes; providing a positive dn/dT lens to collimate said high power laser beam and positioning said positive dn/dT lens in collimating relation to said high power laser beam, said positive dn/dT lens having an index of refraction; providing a focusing lens assembly to focus said high power laser beam and positioning said focusing lens assembly in focusing relation to said collimated laser beam; and including as a part of said focusing lens assembly at least one lens having a negative dn/dT to offset a heat-induced change in the index of refraction of said positive dn/dT lens.