Gradient-field permanent-magnet spin-flip laser

A CO-laser-pumped InSb CW spin-flip Raman laser has been operated in a permanent magnet (∼1500 G) incorporating a field gradient that permits frequency tuning by moving the magnet relative to the InSb sample. Output lines up to the fifth Stokes and the second anti-Stokes are observed. Real-time Doppler-limited absorption spectroscopy employing a small external modulation coil is demonstrated.