Phase Matching Achieved in Circularly Polarized Waves Available to Purchase

C. Kumar N. Patel and Nguyen Van Tran report that they have obtained phase matching between circularly polarized waves in nonlinear interactions (Appl. Phys. Lett. 15, 189, 1969). Phase‐matched interactions in linearly polarized waves have made use of the birefringence in crystals. However, this technique cannot be extended to circular polarizations because the rotary dispersion in crystals exceeds the rotary birefringence. Patel and Van Tran applied a magnetic field to an electron plasma in a semiconductor to increase circular birefringence. The field was aligned along the common directions of propagation of two circularly polarized input waves and the output wave generated by phasematched difference frequency mixing. The magnetic field allows tunability of phase matching for different input frequencies.