Microwave optical modulation by using the electro-optic effect in total internal reflection at the critical angle

We demonstrate microwave modulation of an optical beam by using the electro-optic effect in total internal reflection near the critical angle. An internally reflected mode-locked laser beam and a microwave field electrooptically interact near the surface of a KDP crystal to produce new modulation frequencies in the reflected beam. Its microwave sensitivity is approximately 3 mV/V radicalHz. This technique, described by the boundaryvalue problem of nonlinear optics, provides a sensitive method to study the physical nature of the electro-optic effect in total internal reflection. Fundamental optical and electrical properties of the electro-optic effect in total internal reflection are presented.