Abstract

The gain in an XeF-pumped H₂ Raman amplifier has been measured as a function of the variable delay between the incident pump and Stokes beams. The experiments were performed with spatially filtered, near-Gaussian pump and Stokes beams (see Fig. 1), Our measurements of the absolute peak gain as a function of the relative path lengths are shown in Fig. 2. We observe twenty-two maxima in the gain over the 40-mm distance with a peak gain enhancement of ~150. This is in marked contrast to the single peak of enhancement about equal to 15 for 2X YAG- pumped H₂ (Ref. 1) and XeCI-pumped H₂.² The peaks are separated by ~1.8 mm. This separation appears to correspond generally to the inverse of the separation in cm^-1 of the two strong spectral features of the 351-nm line (~5.7 cm^-1). We believe that the structure observed in Fig. 2 is caused by this line, which contains 60% of the laser energy and has a peak spectral intensity 2.3 times that of the 353-nm line and 110 times that of the 349-nm line.

© 1987 Optical Society of America