Nanocrystals of PbSe core, PbSe/PbS, and PbSe/PbSxS(1-x) core/shell as saturable absorbers in passively Q-switched near-infrared lasers. - Brumer M; Sirota M; Kigel A; Sashchiuk A; Galun E; Burshtein Z; Lifshitz E (Applied optics, 2006)