Simultaneous tunable raman and fixed frequency oscillation of a CH3F FIR laser

Experimental observation of simultaneous oscillation at the Raman frequency and a cascade frequency in a broadly tunable¹³CH3F far-infrared laser is reported. Oscillation on both components persists over the full 25 GHz separation between thev_{3}R(36)andR(37)lines. This observation is in marked contrast to the behavior of the tunable¹²CH3F FIR laser which produces only the Raman frequency when it is optically pumped at lowerJvalues in the same branch. A marked qualitative difference in the large-scale emission spectra for the two lasers is also discussed.