Polariton dispersion of periodic quantum well structures

We studied the polariton dispersion relations of a periodic quantum-well structure with a period in the vicinity of half the exciton resonance wavelength, i.e., the Bragg structure. We classified polariton modes using an approximation of a large number of quantum wells. The polariton effective masses are found to be very small and equal to 10(-3)-10(-4) of the free-electron mass. (C) 2002 MAIK Nauka/Interperiodica.