Tunable Spin-Flip Laser and Infrared Spectroscopy

We investigate the use of a tunable spin-flip Raman laser in infrared absorption spectroscopy. The Raman laser is tunable from 10.9 to 13.0 μm with linearity and resettability of tuning better than ∼4 ÅA at ∼12.0 μm. This limit is set by the present measurement capability. A study of the absorption spectrum of N${\mathrm{H}}_3$ in the 12.0-μm region shows that the spin-flip Raman laser is superior to a conventional grating spectrometer in attainable resolution.