Abstract

Rotational stimulated Raman scattering in N₂ was recently observed¹ at Lawrence Livermore National Laboratory when the Nova beam was propagated through 100 m of air. Stimulated Raman scattering in N₂ will limit the maximum intensity that can be transmitted by air if the frequency and divergence of the laser are to remain unchanged. Modeling of this process requires knowledge of the Raman gain as a function of density and temperature for the N₂ Raman lines. Using stimulated Raman gain spectroscopy, we have measured the temperature dependence of the density broadening coefficient for the Stokes branch rotational lines of N₂. At 295 K, our experimental broadening coefficients are in agreement with the corrected ab initio theory.² The absolute value of the S(10) gain coefficient was determined by ratioing the N₂ gain to that observed for the S(0) transition in H₂. From these data, we have calculated the temperature, wavelength, and J dependence of the Raman gain coefficient in the high density limit, which is in agreement with the value derived from the Livermore experiments.

© 1985 Optical Society of America