Room-temperature gain at 1.3 mu m in PbS-doped glasses

We report on room-temperature optical gain at the ground exciton transition of PbS quantum-dot-doped glasses while optical pumping into the next-highe r exciton resonance. The material gain in the quantum dots is as large as 8 0 cm(-1). The dot-size selective excitation provides tunability of the opti cal gain. This is demonstrated by tuning the gain from 1317 to 1352 nm by c hanging the pump wavelength from 900 to 980 nm. (C) 1999 American Institute of Physics. [S0003-6951(99)00146-1].