Net Optical Gain from PbS Quantum Dot‐Doped Glasses under Continuous‐Wave Pumping

Abstract Lead chalcogenide quantum dots (QDs) have been considered promising gain media in the near‐infrared region. Precipitation of lead chalcogenide QDs into glasses can significantly improve their stabilities and processabilities using mature fiber‐optic technologies and has great potential for application as a broad‐band optical amplification in optical telecommunication. However, the net optical gain of lead chalcogenide QD‐doped glasses has not been realized upon continuous‐wave (CW) pumping, hindering their application as fiber‐optic amplifiers. Here, the study reports a heterostructured PbS/NaCl QD‐doped glass and realizes a net optical gain in the near‐infrared region upon CW pumping. The photoluminescence quantum efficiencies of these QD‐doped glasses are boosted to 43–75% with significantly improved photo/thermal stabilities, and the gain threshold is reduced to ∼single exciton level due to the passivation and charge doping of the PbS QDs by the NaCl wrapping. As a result, net optical gain in the conventional band of telecommunication is realized from the 1 mm thick PbS QD‐doped glasses under CW pumping.