Intermodal tuning behavior of an etalon-tuned three-mirror TEA CO/sub 2/ laser

The detailed tuning behavior within a single ro-vibrational line of a TEA CO/sub 2/ laser was studied by using a wedged etalon and a pyroelectric array. The fine tuning of the laser was performed by using a temperature controlled etalon inside a three-mirror resonator. As the laser wavelength was scanned at a constant rate, single-longitudinal-mode pulses were observed approximately 82% of the time. Two-mode operation occurred over a narrow tuning range near the midpoint between successive cavity modes. The detailed structure of the staircase-like mode-to-mode tuning curve and the corresponding output intensity variations are explained using a simple theoretical model.<
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