Micro- and nano-laser sensing: Principles and applications

Optical micro- and nano-resonators can significantly enhance the interaction between light and matter due to the ultra-high Q factor and ultra-small mode volume, making them ideal platforms to realize low-threshold and narrow-linewidth lasing, and high-precision sensing. In active resonators, the cavity loss can be compensated by the optical gain, thus to reduce the linewidth of the transmission spectrum. Furthermore, the increasing of the slope of the lasing threshold curve and the narrowing of the spectral linewidth occur simultaneously during the lasing state. As a result, the sensitivity and resolution are improved, and then the detection limit is lowered when micro- and nano-lasers are applied in optical sensing. At present, micro- and nano-lasers with various structures have shown great potential in physical field detection including temperature, stress, and angular velocity, and biochemical sensing, such as gas sensing, ion detection, and cell labeling. This review discusses the generation mechanisms, sensing mechanisms, and sensing performance advantages of micro- and nano-lasers. Then, recent progress of micro- and nano-laser sensing is summarized comprehensively. Finally, the future research trend of micro- and nano-laser sensing is prospected.