Optical seminar | 09 July 2021

Wavelength-scale lasers provide promising applications through low power consumption requiring for optical cavities with increased quality factors. Cavity radiative losses can be suppressed strongly in the regime of optical bound states in the continuum (BICs); however, a finite size of the resonator limits the performance of BICs as cavity modes for active nanophotonic devices. Here, we employ the concept of a super-BIC mode created by merging
symmetry-protected and accidental BICs in the momentum space, and realize an efficient laser based on a finite-size cavity with a small footprint. We trace the evolution of lasing properties before and after the merging point by varying the lattice spacing, and we reveal that the super-BIC laser demonstrates the significantly reduced threshold, substantially increased quality factor, and shrunken far-field images. 

Main paper/arXiv, related to the seminar, and other references

Min-Soo Hwang, Hoo-Cheol Lee, Kyoung-Ho Kim, Kwang-Yong Jeong, Soon-Hong Kwon, Kirill Koshelev, Yuri Kivshar, Hong-Gyu Park, "Ultralow-threshold super-BIC laser
", Nature Communications, accepted (2021)