An experimental study of normal and stimulated Raman emission in diamond is presented, including measurements of linewidth, intensity, and angular distribution of radiation having a frequency shift of 1332.0 ${\mathrm{cm}}^{-1\mathrm{}}$. The diamond crystal formed a Raman resonator; excitation was by a giant-pulse ruby laser. The dependence of normal Stokes emission on laser intensity and the threshold for oscillation were investigated. A value for the Raman gain ($g=6.9\mathrm{}\times {10}^{-3\mathrm{}}$ ${\mathrm{cm}}^{-1\mathrm{}}$ per MW/${\mathrm{cm}}^2$) was calculated from the measured linewidth ($\Delta \nu =2.04\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$) and cross section for scattering, and found to be in good agreement with a value determined from the threshold for oscillation. The angular distributions of anti-Stokes and Stokes emission and absorption for parallel and convergent laser light are also in good agreement with theory: The emission cone angles are strongly dependent on the angle of convergence of the incident light, and it is established that the preferred directions for emission are those making use of the most intense first-order Stokes radiation which is peaked in the forward direction within the Raman resonator.

• Received 10 September 1969

DOI:https://doi.org/10.1103/PhysRevA.1.628