Single-cystal erbium chloride silicate nanowires with internal net gain larger than 300 dB/cm

A record level of spatial-averaged internal net gain larger than 300 dB/cm is demonstrated at 1532 nm from a single-crystal Erbium Chloride Silicate nanowire. Signal enhancement at small signal regime was resolved along the entire nanowire. Pump power dependence of gain saturation are studied.