Experimental and theoretical study of exciton surface polaritons on organic crystals. I. (010) Face of TCNQ° single crystals

Abstract

An exciton surface polariton has been observed at room temperature by the technique of attenuated total reflection (ATR) spectroscopy on the (010) face of tetracyanoquinodimethane (TCNQ°) single crystals. From the p-polarized reflectivity as a function of the angle of incidence at constant wavelength, the experimental dispersion of the surface mode and the real and imaginary part of the dielectric function were determined in the wavelength region 515-425 nm. Supporting theoretical studies also reported include a calculation of the dispersion curve of a free exciton surface polariton, the calculation of perspective figures representing the ATR at fixed prism-crystal gaps for variable frequency and angle of incidence, and the calculation of the intensity of the electromagnetic field in the prism, gap and the crystal. © 1979 American Institute of Physics.