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Extending the Tuning Range of Short-Pulse Lasers by Transient Stimulated Raman Scattering in Gases

Transient stimulated Raman scattering (SRS) is a convenient method to extend the tuning range of short-pulse lasers. In this paper we present results obtained by using 400 nm pump pulses of 2.5 ps duration. After briefly reviewing earlier work on transient SRS in pure hydrogen and in H2/CH4 mixtures, we discuss new experiments on transient SRS in mixtures of HD with hydrogen and deuterium. In gas mixtures additional components, corresponding to the sum- and difference-frequencies of the components of the individual gases, are observed. In HD/H2 mixtures, up to 6% of the pump pulse energy can be converted into the strongest combination line (-1/-1). From the experimentally determined optimum partial pressure ratios a differential Raman-cross section of 3.0×10-30 cm-2/sr was derived for the HD molecule.