Total Reflection Phenomena in Second-Harmonic Generation of Light

The direction, polarization, and intensity of second-harmonic light beams generated in a crystal of NaCl${\mathrm{O}}_3$ have been observed as a function of the angle of incidence, when the primary laser beam is incident from a denser linear fluid. When the angle of incidence ${\theta }_i$ is smaller than the critical angle for total reflection ${\theta }_{\mathrm{crit}}\left(\omega \right)$, a reflected harmonic beam and two distinct spatially resolved transmitted harmonic beams with polarizations precessing in opposite senses are observed. When ${\theta }_{\mathrm{crit}}\left(2\mathrm{}\omega \right)>\mathrm{}{\theta }_i>{\theta }_{\mathrm{crit}}\left(\omega \right)$, the incident laser power is totally reflected, but one of the transmitted harmonic beams still exists. For ${\theta }_i>{\theta }_{\mathrm{crit}}\left(2\mathrm{}\omega \right)$, only the reflected harmonic beam remains. When two totally reflected laser beams are incident from opposite sides of the normal, second-harmonic radiation occurs in the direction of both the inward and outward normal. The results agree quantitatively with the theory of Bloembergen and Pershan.