Abstract

The pulsed Raman technique utilizing a Q-switched frequency-doubled Nd:YAG laser and a pulse-activated nanosecond photon-counting detection system has been used to reduce the fluorescence background in Raman spectra when the fluorescence-pump lifetime is much shorter than the duration of the laser output pulse. A fluorescence discrimination factor shows the improvement of the Raman signal-to-noise ratio obtained with pulsed Raman over cw Raman. Dark-current-limited operation can be virtually eliminated using the pulsed Raman technique. When applied to a sample of Mn-doped ZnSe using an uncooled 1P28 photomultiplier and about 10 mW of average laser power at 532 nm, a 60-count/s fluorescence peak of 125-μs lifetime, observed with a 200-μs detection interval, was reduced by a factor of ≳60 with a 1-μs detection interval. The computed factor is 63.

© 1972 Optical Society of America

Modulated Spectra of ac Arc Lamps

P. L. Patterson
J. Opt. Soc. Am. 62(5) 627-633 (1972)

Enhancement of Absorption Spectra by Dye-Laser Quenching, II*

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Measurement of the Light-Field Amplitude-Correlation Function through Joint Photon-Count Distributions*

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J. Opt. Soc. Am. 62(6) 792-796 (1972)

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High-Resolution Raman Spectroscopy of Gases with Laser Sources, V.* Use of the Single-Mode Argon Laser†

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