Measurements of infrared optical parametric fluorescence are reported for the first time. Using a pump wavelength of 1.064 µ in LiNbO3 , observations of the fluorescence power, bandwidth, and angular dependence at 1.63 µ are in good agreement with a plane-wave theory. The operating characteristics of two pulsed, internal, doubly resonant parametric oscillators are also reported and compared with predictions of the fluorescence measurements. With measured thresholds on the order of 400–700 W, the two oscillators provided nearly continuous tuning from 1.51 µ to 3.55 µ with average powers of 6 mW and peak powers of 600 W. These powers represent available pump conversion efficiencies of 10% and 50%, respectively. Oscillating bandwidths were only 10% of the fluorescence bandwidth and ranged from 1.7 cm -1 to 45 cm-1, depending on the output wavelength. Longitudinal mode structure and multiple pulsing of the oscillators were observed.
James E. Pearson, Amnon Yariv, and Uri Ganiel, "Observations of Parametric Fluorescence and Oscillation in the Infrared," Appl. Opt. 12, 1165-1171 (1973)