Interference of resonance luminescence of exciton polaritons in CuGaS2 crystals

The nonmodulated and wavelength-modulated reflection spectra of CuGaS2 crystals for the polarization EIIc of 10 K are studied. The states n = 1, 2 and 3 of the excitons Γ4 (A-excitons) and n = 1, n = 2 of B- and C-excitons are found. The nonmodulated absorption spectra for the polarization E⊥c at 10 K have been studied. The states n = 1, 2 and 3 of Γ5 excitons are found. The main parameters of the A (Γ4, Γ5) and B, C exciton series at the energies of the longitudinal and transverse excitons Γ4 for the states n = 1 and n = 2, the effective masses of electrons (me1∗) and holes (mv1∗,mv2∗,mv3∗) are determined. The photoluminescence peaks were observed at n = 3 and n = 4 of the excitons Γ5 in the luminescence spectra excited by the line 4880 Å of Ar+ laser. In the luminescence spectra the interference is found.