We use a frequency-shifted feedback technique with a high-gain fiber amplifier operating at λ=1083 nm to produce a multifrequency light beam that covers a controllable spectral range. It is ideal for optically pumping a gas of metastable He because it spans the Doppler width, and its high efficiency has implications for many applications. Measurements confirm that eight times fewer atoms are left in the unchosen states with multifrequency light.
© 2000 Optical Society of America
(060.2320) Fiber optics and optical communications : Fiber optics amplifiers and oscillators
(140.0140) Lasers and laser optics : Lasers and laser optics
(140.5560) Lasers and laser optics : Pumping
(170.3880) Medical optics and biotechnology : Medical and biological imaging
(190.2640) Nonlinear optics : Stimulated scattering, modulation, etc.
M. Cashen, V. Bretin, and H. Metcalf, "Optical pumping in 4He with frequency-shifted feedback amplification of light," J. Opt. Soc. Am. B 17, 530-533 (2000)