摘要 |
A method for thermally compensating lenses in an optical system for high power lasers includes the steps of providing a fused silica lens to collimate a high power laser beam and positioning that lens in collimating relation to the laser beam. A focusing lens assembly is provided to focus the collimated laser beam and is positioned in focusing relation to the collimated laser beam. At least one lens having a negative dn/dT to offset a heat-induced change in index of refraction of the fused silica lens is included as a part of the collimating lens assembly and as a part of the focusing lens assembly. The lens having a negative dn/dT is selected from a group of glasses having a negative dn/dT. The power of the lenses is balanced with an offsetting negative dn/dT so that the optical system maintains its focus over a wide temperature range.
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