Resonance Raman Scattering in InSb near theE1Transition

Resonance Raman scattering in InSb near the $E_1$ transition has been measured at low temperatures for various different configurations with a tunable dye laser. The experimental curves show a resonance peak at an incident photon energy appreciably higher than the energy of the $E_1$ peak in the reflectivity spectra, contrary to the predictions of existing theories. Double resonance in the Raman tensor involving transitions in the band continuum is proposed to explain the result.