Grating-induced slow-light enhancement of second-harmonic generation in periodically poled crystals

Abstract

The effect of slow light on second harmonic generation in a periodically poled χ (2) nonlinear medium is investigated theoretically. A linear π phase shifted grating is used to slow the group velocity of the fundamental frequency and the resulting field enhancement greatly increases the second harmonic conversion efficiency. A second linear grating at the input end ensures that all output is in the forward direction. We show that almost 100% conversion efficiency can be achieved for continuous wave pumping at low intensities that generate negligible conversion in the absence of the slow-light grating.