Giant optical gain in a single-crystal erbium chloride silicate nanowire

Rare-earth optical materials with large optical gain are of great importance for a wide variety of applications in photonics and quantum information due to their long carrier lifetimes and quantum coherence times, especially in the realization of efficient lasers and amplifiers. Until now, such materials have achieved a gain of less than a few dB cm(-1), rendering them unsuitable for applications in nanophotonic integrated circuits. Here, we report the results of the signal enhancement and transmission experiments on a single-crystal erbium chloride silicate nanowire. Our experiments demonstrate that a net material gain over 100 dB cm(-1) at wavelengths around 1,530 nm is possible due to the nanowire's single-crystalline material quality and its high erbium concentration. Our results establish that such rare-earth-compound nanowires are a potentially important class of nanomaterials for a variety of applications including, for example, subwavelength-scale optical amplifiers and lasers for integrated nanophotonics, and quantum information.