Low-threshold and controllable nanolaser based on quasi-BIC supported by an all-dielectric eccentric nanoring structure

• DOI: 10.1364/oe.420001
• Publication Date: 2021-03-31T14:00:09Z
• Authors: Weilin Bi; Xin Zhang; Meng Yan; Lina Zhao; Tingyin Ning; Yanyan Huo
• Keywords: 0103 physical sciences; 02 engineering and technology; 0210 nano-technology; 01 natural sciences

High-Q factor can enhance the interaction between light and matter, which is an important parameter to decrease the threshold of nanolasers. Here, we theoretically propose an eccentric nanoring structure with a high and controllable Q factor to realize a low-threshold and controllable nanolaser by amplifying the quasi-bound states in the continuum (quasi-BIC). The designed nanostructure supports a quasi-BIC because of the symmetry protection-breaking of the nanostructure. The quasi-BIC has a very high Q factor of about 9.6×104 and can also be adjusted by changing structural parameters. We use the energy level diagram of the four-level two-electron system to study the lasing action of the eccentric nanoring structure. The results show that the nanolaser has a relatively low threshold of about 6.46 μJ/cm2. Furthermore, the lasing behavior can be tuned by controlling the structural parameters of the eccentric circular ring structure.