RESUMO
We show that a quasi-steady-state photorefractive spatial soliton forms a waveguide structure in the bulk of a photorefractive material. Although the optically induced waveguide is formed by a very low-power (microwatts) soliton beam, it can guide a powerful (watt) beam of a longer wavelength at which the medium is nonphotosensitive. Furthermore, the waveguide survives, either in the dark or when guiding the longerwavelength beam, for a long time after the soliton beam is turned off. We take advantage of the solitons' property of evolution from a relatively broad input beam into a narrow channel and show that the soliton induces a tapered waveguide (an optical funnel) that improves the coupling efficiency of light into the waveguiding structure.
RESUMO
We study experimentally self-trapping of optical beams in photorefractive media and show that the trapping is inherently asymmetric with respect to the two (transverse) trapping dimensions. We also present experimental results that show how the sizes of the resultant photorefractive spatial solitons are independent (within their range of existence) of the amplitude of the externally applied electric field used to generate them.
RESUMO
We present a theoretical analysis of the stability of photorefractive spatial solitons along with experimental results that show that the solitons are stable for small-scale perturbations but break down when the perturbations exhibit a transverse scale comparable with the soliton size (cross section).
