System for minimizing the depolarization of a laser beam due to thermally induced birefringence
US5504763A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 19, 1995 |
| Grant date | Apr 2, 1996 |
| Priority date | — |
| Expiry date | Jul 19, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01S2301/206
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A system is disclosed for minimizing the depolarization of a laser beam due to thermally induced birefringence in a rod-shaped gain medium over a wide range of excitation levels. After passing through the gain medium, the polarization of the beam is rotated by ninety degrees and either redirected back into the same gain medium or a substantially identical gain medium. By this arrangement, the portion of the beam that was radially polarized during the first pass is tangentially polarized during the second pass so that the original polarization is restored. In order to maximize the compensation, a relay image system is used to generate an image of the beam in the gain medium as it existed during the first pass and project that image into the gain medium during the second pass. The magnification of the relayed image is substantially one to one with respect to the actual image. By using a relayed image with a unity magnification, the size of the beam and the angle and the position of the rays in the beam are preserved at varying thermal loads. In this manner, maximum coincidence of the rays during the two passes is achieved. In the case of asymmetric pumping, performance can be enhance…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.