Beam modulated fanning in a crystal BaTiO_3

摘要

Communication systems require devices that allow rapid distribution of signals to multiple users. We presented a proposal for a demultiplexer based on the fanning effect. Beam fanning is a process similar to two-beam coupling, except in this case, in where only one beam is incident on the material and its energy is transferred into scattered light. As a result of the energy transfer, scattered light is amplified, and a "fan" is observed. Since energy transfer direction can be changed by switching the polarity of the applied electric field, beam fanning effect can be maximized or minimized on depending of the polarity. We propose an optical router method with the photorefractive beam-fanning. In this method, a Gaussian modulated beam passing through a photorefractive BaTiO_3 crystals spreads into a some beams that arises from stimulated scattering. This fanning can be controlled changing the polarization of the beam or the incident angle toward the crystal. Each scattered beam maintains the input modulated frequency in a wide range. Our results show the possible application of the fanning effect as an optoelectronic demultiplexer.