The first part of this work describes theoretical and experimentalstudies of Stark-induced three-wave mixing in gaseous NH2D. Applicationof a dc electric field to a gaseous system destroys the basic inversionsymmetry and allows two-photon mixing processes to occur. A theoretical derivation of this effect under conditions of resonantly enhancednon-linearities is given for a three-level system. Calculations are presentedfor mixing of a CO2 laser with a 4 GHz microwaves in the molecule NH2D,producing single lower sideband radiation.
Experimental observation of resonantly enhanced, dc-induced, three-wave mixing in gaseous NH2D is presented. The dependence of this effecton gas pressure, microwave frequency, applied dc field, and microwavepower are presented and compared with theoretical predictions. Theexperiment was done at Hughes Research Laboratories by Abrams and his coworkers.
The second part of this work describes the propagation of electromagneticwaves in periodic layered media. The propagation of electromagneticradiation in periodically stratified media is considered. Mediaof finite, semi-finite and infinite extent are treated. A diagonalizationof the unit cell translation operator is used to obtain exactsolutions for the Bloch waves, the dispersion relations, and the band structure of the medium.
The theory of electromagnetic Bloch waves in periodic stratifiedmedia is then applied to the problems of birefringence, and group velocityin these media. The relevance of periodic media to phase matchingin nonlinear mixing experiments-and to laser action in the x-ray regionis discussed.
New types of guided waves such as Bragg guided waves and opticalsurface waves are theoretically predicted and experimentally observed.
