Helium spectroscopy using an InGaAs laser diode.
Absorption spectroscopy in (3)He and (4)He has been performed with an InGaAs single-mode distributed Bragg reflection laser diode. The laser source provides as much as 120 mW of single-mode, single-frequency output in the 1083-nm region of the spectrum. Frequency tuning of the laser diode output by means of the junction temperature allows for mode-hop-free scanning of the entire 2(3)S-2(3)P manifold in both the (3)He and (4)He absorption spectra. The authors believe this to be the first report of semiconductor laser spectroscopy at this wavelength. Such a device will have significant applications in optical pumping, atomic cooling and trapping, fundamental nuclear studies, magnetometry, and gas dynamics.
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Bohler
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Marton