Difference frequency generation between the output waves of the PP-MgO:LN optical parametric oscillator

Abstract

The difference frequency generation in the AgGaSe₂ crystal between output waves of a periodically poled MgO doped lithium niobate (PP-MgO : LN) optical parametric oscillator (OPO) is described in this paper. The wavelength of the generated radiation is tunable from 6 to 13 µm with the average generated power in the range of several microwatts. The set-up allows a rapid tuning of the wavelength in the limited region of spectra without changing the temperature of the PP-MgO : LN crystal. A typical spectral linewidth of 5 cm^-1 makes this source suitable for spectrometry of complex molecules under atmospheric conditions. The measured spectrum of the acetone vapour is presented to confirm this fact.
Keywords: nonlinear optics, optical frequency converters, infrared sources
PACS: 42.65.-k, 42.79.Nv, 42.72.Ai