Theoretical Analysis of Polariton Interference in a Thin Platelet of CuCl. I. Additional Boundary Condition

Interference patterns in reflectance and transmittance of a thin platelet of CuCl in the Z3 exciton region have been analyzed in terms of an extended version of the D'An-drea-Del Sole theory about microscopic treatment of additional boundary condition (ABC). In the extension, quantization effect has been explicitly considered with respect to exciton motion in a slab. The effect of internal multiple reflection of polariton waves and the energy dependence of exciton damping factor have been taken into account. The decay constant of the evanescent exciton wave near surface has been treated as an adjustable parameter. The observed spectra by Mita and Nagasawa are well reproduced by the simplest extreme case of this theory, i.e., the case of vanishing contribution from the evanescent wave, which is equivalent to the Pekar's ABC. © 1985, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.