Photo-modulated photoluminescence in III-V semiconductor quantum wells

We have developed a new technique of modulated photoluminescence (PL) spectroscopy. We show that the signal detected at twice the modulation frequency of the exciting light contains information about the non-linear processes similar to photomodulated PL experiments. We attribute this non-linear PL signal to the optical modulation of the internal electric field of the quantum well (QW) samples. The method allows the separation of overlapping PL emission lines and provides the emission parameters of the separated lines, even when the PL spectrum itself appears to be featureless.