Fundamental spatial mode size control of holographic laser oscillators

The spatial transient behaviour of the fundamental mode of a self-adaptive holographic laser oscillator was studied by using transfer matrix methods. The study began by considering a simple laser oscillator consisting of a pl ane output coupler and a nonlinear four-wave mixing (FWM) medium in a self- intersecting loop geometry. The system was then modified to consider infini te and finite FWM media, and additional intra-loop optical elements, such a s lenses and Gaussian transmittance apertures. Results show that it is poss ible to generate and maintain the oscillation of large-volume modes allowin g high energy extraction as well as good phase-conjugate quality and low-lo ss operation.