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
Full Article | PDF ArticleMore Like This
P. L. Patterson
J. Opt. Soc. Am. 62(5) 627-633 (1972)
Richard A. Keller, Edward F. Zalewski, and Norman C. Peterson
J. Opt. Soc. Am. 62(3) 319-326 (1972)
P. Furcinitti, J. D. Kuppenheimer, L. M. Narducci, and R. A. Tuft
J. Opt. Soc. Am. 62(6) 792-796 (1972)