ABC-THEORY OF AN EXCITON-POLARITON IN A SLAB

Based on the analytic model of exciton wave function by D'Andrea and Del Sole, which contains an evanescent wave component exp [-PZ] near surfaces, the polarizability χ(R, R';ω) of a slab (thickness d) has been evaluated with an accuracy of neglecting terms of order 0(exp [-Pd]). The effect of size quantization has been properly considered. The solution of Maxwell equation for this slab gives the field as a superposition of bulk-like waves and surface localized amplitudes, together with ABC (Additional Boundary Condition) for the coefficients of superposition. With this result, the validity of previous treatment of the same model by Cho and Kawata (CK) with a less accurate approximation has been checked, and it is shown that the optical spectra calculated by the final version of CK's ABC give an excellent agreement with those by the present theory in its validity region, i.e., for the values of d outside the quantum well regime. © 1990, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.