Ultracompact multibound-state-assisted flat-band lasers
Highly compact lasers with a low threshold and stable single-mode operation are in great demand for integrated optoelectronics. However, considerable side leakages and radiation losses in small cavities substantially degrade the quality (<i>Q</i>) factor, posing a substantial obstacle in pursuing high-performance miniature lasers. Here we propose and experimentally demonstrate a flat-band laser supplemented by multiple bound states in the continuum. By simultaneously confining light in all three dimensions, a high <i>Q</i> factor of ~1,440 in an ultracompact terahertz quantum cascade laser cavity with a lateral size of ~3<i>λ</i> is reported. The field confinement makes it possible to realize an electrically pumped single-mode terahertz laser with a low threshold current density, despite the small device footprint. This surface-emitting laser emits a well-defined beam with good directionality. The demonstrated multibound-state-assisted flat-band design is also applicable to other wavelength regimes, offering a route to energy-efficient, monolithically integrated and ultracompact laser sources that suit a wide range of applications.
Authors
- A. G. Davies (ORCID: https://orcid.org/0000-0002-1987-4846)
- E. H. Linfield (ORCID: https://orcid.org/0000-0001-6912-0535)
- Jieyuan Cui (ORCID: https://orcid.org/0000-0002-7990-1113)
- Qijie Wang (ORCID: https://orcid.org/0000-0002-9910-1455)
- Yunda Chua
- Bofeng Zhu (ORCID: https://orcid.org/0009-0002-6189-6229)
- Lianhe Li (ORCID: https://orcid.org/0000-0003-4998-7259)
- Song Han (ORCID: https://orcid.org/0000-0001-7138-4214)
- Qian Wang (ORCID: https://orcid.org/0000-0003-0750-7843)
- Chongwu Wang (ORCID: https://orcid.org/0000-0002-8749-196X)
Institutions
- Agency for Science, Technology and Research (SG)
- University of Leeds (GB)
- Zhejiang University of Science and Technology (CN)
- Nanyang Technological University (SG)
- Institute of Materials Research and Engineering (SG)
- National Engineering Research Center of Electromagnetic Radiation Control Materials (CN)
Publication Details
- Journal
- Nature Photonics
- Published
- 2025-04-28
- DOI
- https://doi.org/10.1038/s41566-025-01665-6
- Citations
- 21
- Primary Topic
- Photonic and Optical Devices
- Type
- article
- Field-Weighted Citation Impact
- 15.34
Funders
- National Research Foundation
- National Research Foundation Singapore
- National Natural Science Foundation of China
- Zhejiang University
- Medical Research Council
- Engineering and Physical Sciences Research Council
- National Medical Research Council