Compact Unidirectional Laser Based on All-Dielectric Metasurface With High Quality Factor

All-dielectric metasurfaces offer unconventional optical functional behaviors for manipulating light, due to the strong localization of light with negligible dissipative loss. Here, we propose a compact design for a light emission cavity consist of an all-dielectric grating reflector and an all-dielectric symmetry-breaking metasurface supporting “dark” mode. The “dark” mode of the asymmetric metasurface structure results in high quality factor, and the broadband perfect reflector leads to directional emission. We present a theoretical study of the spectral characterization of the emission cavity, and the emission property of the nanocavity embedded with gain medium is investigated by a Maxwell-Bloch Langevin approach. Strong luminescence enhancement with directive light emission and reduced lasing threshold are observed. Our observations offer enormous potential in controlling light emission and provides an essential step for developing efficiency and directionality LEDs, and ultra-compact lasers.