Computer controlled infrared parametric oscillator source

Previously we have reported on the LiNbO3 angle tuned parametric oscillator and its potential for computer control and operation as a coherent spectrometer.1 In this paper we report the operation of the parametric oscillator under full interactive computer control. The present system allows the user to choose the starting wavelength, scan range, scan rate, and resolution. The computer controls the stepper motors that rotate the LiNbO3 crystal and line narrowing grating. The user can also designate a data file for recording the spectral data on disk for later display on an x-y recorder. With the present system we have generated a coherent anti-Stokes spectrum2 of H2 gas at gas pressures from 1 atm to below 10 Torr. The absolute wavelength resettability of the parametric tuner determined from the spectrum was ±0.2 cm−1 at a resolution of 2 cm−1. Additional line narrowing with an etalon led to line-widths of less than 0.2 cm−1.