Abstract

In self-focusing media a plane wave of infinite extent breaks-up into a periodic array of individual intensity maxima. This has been reported in bulk quadratic and photorefractive media, but not in slab waveguides for which analytical theories exist.^1,2 When the spatial beam profile contains a Fourier spectrum of spatial components, either due to noise or due to an injected periodic signal (seeding case), a range of these spectral components (noise case) or a single component (seeded case) can grow exponentially to produce periodic field structures. They are parameterized by the beam intensity I, the period Ʌ (=2π/κ) and the gain γ coefficient. For the noise case, the periodicity with the maximum gain (for a given intensity) wins out. For the seeded case, the injected periodic structure grows preferentially and the gain coefficient can be measured.

© 2001 Optical Society of America