Periodically poled LiNbO 3: Optical parametric oscillation at wavelengths larger than 4.0 μm with strong idler absorption by focused Gaussian beam

Abstract

Coupled-wave equations for focused Gaussian beams in an optical superlattice are derived. By solving the coupled equations, we investigate theoretically the optimum design parameters for the middle-infrared wavelength generation under the configuration of a singly resonating optical parametric oscillation with strong idler absorption. A positive dephasing is required due to the Gouy effect for optimal idler generation. For idler wavelengths of up to 5.0 μm, the threshold power can be kept at a lower level over a wider range of dephasing. Beyond this, the threshold power increases with the absorption coefficient of the idler wave. This model accurately predicts the current experimental results with weaker idler absorption. Validation with strong idler absorption is also verified. © 2005 American Institute of Physics.