3.35 μm intracavity difference frequency generator with single pump input

Compact, CW laser sources with output wavelengths that are matched to the fundamental absorption bands of certain molecules are required for remote sensing, pollution analysis, and medical monitoring. Although Pb-salt diodes have output wavelengths in the desired spectral region, they are quite expensive and operate exclusively at cryogenic temperatures. Nonlinear difference frequency generation is an alternative method of generating output for these applications. In this paper we describe the results of initial experiments in which a 0.807 μm input beam was mixed with the intracavity field of a 1.06-μm laser to generate difference frequency output at 3.35 μm. The input beam was also used to pump the Nd:YAG laser, thus the device needs only one optical input