Quasi-BIC Lasing at Telecom Wavelengths and Its Potential Application in Biosensing

Bound states in the continuum (BIC), a phenomenon enabled by dielectric lattices, have been actively investigated for achieving remarkable improvements in quality factors, light-matter coupling, lasing, and Bose-Einstein condensation. Although there have been various progresses in using complex unit cell structures, their full potential has not yet been fully realized. Here, we show that dielectric lattices support lasing in an ultrahigh quality factor quasi-BIC mode with telecom-wavelength emission, which holds potentials for efficient and useful communication applications. Besides, our numerical analysis shows that the optical spectrum of the compact laser is highly influenced by the changes in the refractive index (RI) of the surrounding environment. Specifically, as the RI is modified with a step of 10(-3) , the wavelength of the laser beam shifts linearly toward longer wavelengths. This means that even slight variations in the RI can significantly impact the spectrum of the laser, making it a highly sensitive tool for measuring changes in the liquid environment. The calculated sensitivity and figure of merit (FOM) are 230 nm/RI unit (RIU) and 742 RIU-1 , respectively, which reflect the promising performance and efficiency of the device as a biosensor. Therefore, the proposed device holds potentials in telecom range light source and biosensing applications.