Recently, the team led by Prof. Chen Shuqi and Prof. Tian Jianguo of Nankai University has made important progress in the field of bound states in the continuum (BICs) nanolaser. The team proposed full-k-space BICs by engineering the complex Fourier components of the dielectric constant of microstructure to control the Bragg scatterings, and also realized the arbitrary spatial information modulation of nanolasers intra cavity based on full-k-quasi-BICs. The related results were published in the top international journal Physical Review Letters, entitled “Spatial Information Lasing Enabled by Full-k-Space Bound States in the Continuum”.

Laser technology has become a cornerstone of modern society. The current mainstream nanolasers include microcavity lasers, photonic band gap lasers, and emerging topology lasers. While these micro-nano optical cavities have various mode selection mechanisms, it is difficult to transmit rich spatial information without additional information-loading elements such as modulators or holographic plate. This limits their application in optical interconnection and active photonic integration. BICs attract wide attention for their ultra-high radiation quality factor (Q factor). Controlling the radiation of the non-Hermitian system, BICs can achieve perfect optical binding in the radiation spectrum above the light line as a result of destructive interference induced by strong mode coupling. However, BICs have been considered to be zero-dimensional polarization singularity in momentum space (k-space), and the high-dimensional BICs in momentum space remain unexplored.

Spatial information lasing based on full-k-space BICs

The team led by Prof. Chen Shuqi and Prof. Tian Jianguo advanced a new concept of spatial information lasing based on full-k-space BICs. The engineering of near-field optical parameters changes the mode coupling and therefore modulate the entropy of laser information in the cavity, while simultaneously maintaining high Q and modal gain. The entropy of laser information can be continuously tuned by an all-optical method or the complex Fourier component of dielectric constant. The intracavity modulation of spatial information employs the non-local Bloch mode and the controllable Bragg couplings among modes, while traditional naonlaser cavities use a local mode, which makes it difficult to achieve similar results. Moreover, the asymmetric Bragg scattering process and incident seeding light are used to realize the single-mode output for spatial information lasing. Spatial information lasing based on full-k-space BICs has expanded the  frontiers of integrated optical information generation and amplification, and will promote the development of nonlinear physics, photonic integrated links, and on-chip quantum computing.

Ruoheng Chai, a doctoral student at Nankai University, is the first author, and Prof. Shuqi Chen, Prof. Hua Cheng and Associate Prof. Wenwei Liu are the co-corresponding authors. The School of Physics and the School of Materials Science and Engineering of Nankai University are the affiliations of the first author.

URL:

https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.132.183801

（Edited and translated by Nankai News Team.)