Generation and self-scanning of isolated spots for memory, display, and delay of images

摘要

A two-dimensional (2-D) nonlinear resonator containing a material of intensity-dependent refractive index spontaneously generates remarkable optical patterns. ~(1,2) The spontaneous optical pattern generation had been theoretically and experimentally studied on various setups of the 2-D resonator in combination with a wide variety of materials or devices.~(1-8) D'Alessandro and Firth theoretically proved to exist three kinds of stationary solutions, which are uniform, rolls, and hexagons, in a Kerr slice with a single feedback mirror. ~3 Most of the resonators observed roll and/or hexagons. Non-hexagonal patterns were generated were generated by a specific beam shape or a aperture in the feedback beam line. ~(9,10) In many previous works, the generated patterns were relative homogeneous patterns at the center of beam or in the wide region. As inhomogeneous patterns, there are spatiotemporal turbulent patterns implying wide temporal and spatial frequencies. ~(11) The turbulent pattern is not perfectly controllable. In consideration with the engineering application such as memory, display, and logic operation with maintaining the spatiotemporal dynamics, we require to generate controllable inhomogeneous patterns. We try to generate isolated spots as the first choice of inhomogeneous patterns. The generation of an single isolated spot was demonstrated by use of the external feedback electronics. ~(12) We, however, adopted a simple method based on the spatial frequency filtering technique. In this paper, we demonstrated the isolated spots induced by the external optical input and the self-scanning of the spots, derived from slight slant of the feedback beam.