Efficiency of infrared frequency doubling in periodic layer media

An investigation was made of second harmonic generation in a periodic layer structure with an arbitrary difference between the refractive indices of two neighboring layers. The conditions for phase-quasimatched interaction between the waves are considered. The approximation of a constant power of the input beam is used to calculate the second harmonic amplitude. It is shown that a pile of optically isotropic crystals can be used to generate the second harmonic of a laser beam with an arbitrary polarization. The wide range of optical crystals than can be employed in assembling periodic layer structures suggests that it should be possible to increase the efficiency of frequency multipliers handling infrared and ultraviolet radiation.