Polariton emission from CuGaSe2 crystals

The value of longitudinal-transverse splitting ωLT equal to 2.5-2.8 meV and the translation mass M=2.5m0 were determined for the A exciton as a result of investigation of the reflectivity and luminescence spectra of CuGaSe2 crystals. The emission from the upper and lower polariton branches of the long-wavelength exciton was observed.