Apparatus for and method of extracting an output beam from a laser system

摘要

The output of a laser oscillator is doubly passed through a birefringement medium, a quarter-wave plate and a laser amplifier by reflection from a phase conjugate mirror, the birefringent medium being between the oscillator and the plate in the path of the initial and reflected oscillator output. The birefringent medium divides the oscillator output into a first set of orthogonal polarization components (rays) and refracts one of them at a first angle successively through the plate and amplifier for reflection from the mirror through the amplifier, plate and medium. The reflected ray is amplified and then divided by the medium into a second set of orthogonal ray components which exit the medium at different angles away from the oscillator. In another embodiment, a second quarter-wave plate is added between the amplifier and mirror, and in a third embodiment the amplifier is positioned between the oscillator and the birefringent medium. These designs represent a unique means of separating in angle the oscillator input beam and the phase-conjugated/amplified beam. This results in a physical positional separation of the two, which allows the latter beam to be readily extracted and utilized in a useful fashion, and prevents potentially damaging reflections from being fed back into the oscillator.