Abstract

It is well known that low power cw light beams can exchange energy via photorefractive two- wave mixing. This phenomenon is very useful for wavelengths within the transparency region of the nonlinear material being employed. It would be very interesting to obtain such an effect also at wavelengths that are absorbed by the electrooptic materials. Furthermore, an enhancement of the optical nonlinearity may be obtained at such wavelengths due to resonant effects. We demonstrate here, for the first time to the best of our knowledge, that highly absorbed ultraviolet light beams travelling in a hollow waveguide between two pieces of an electro-optical material can couple and exchange energy via the optical nonlinearity driven by the light distribution of the refracting waves. The effect is believed to be connected with the interband photorefractive effect.¹

© 2002 Optical Society of America