EXCITONIC CHANNEL OF 2-PHONON RESONANT RAMAN-SCATTERING IN A QUANTUM-WELL

The theory of two-phonon resonant Raman scattering with the participat ion of the quasi-two-dimensional (Q2D) excitons as intermediate states is developed for a quantum well (QW). It is shown that the excitonic channel of 2PRRS leads to the sharp enhancement ( in alpha0-3/ln2 alph a0 times, alpha0 is the dimensionless exciton-LO-phonon coupling const ant ) of the 2PRRS cross section in a comparison with the similar proc ess in a bulk semiconductor. This enhancement is due to the possibilit y of the real LO-phonon emission in the excitonic channel.