[18a-A305-1~9] 3.11 Nanoscale optical science and near-field optics (formerly 3.12)

▼ [18a-A305-1] GaN Ultraviolet Laser based on Bound States in the Continuum (BIC)

〇(D)MuHsin Chen¹, Di Xing¹, Vin-Cent Su², Yang-Chun Lee¹, Ya-Lun Ho¹, Jean-Jacques Delaunay¹ (1.The Univ. of Tokyo, 2.Nat'l United Univ.)

Keywords:bound states in the continuum, GaN lasers, ultraviolet lasers

Optical bound states in the continuum (BICs), realizing full suppression of radiative losses, have been utilized to realize strong light confinement and optical modes with high a Q-factor. Lasing actions with narrow linewidths based on BIC modes have been demonstrated in the NIR and the visible ranges, but BIC-based lasers in the UV region have not been reported. As UV light sources are essential in various fields, strategies to design compact UV lasers based on high-Q modes is desirable. Here, we demonstrate the first BIC-based UV laser by designing a 1-D periodic resist structure on top of a GaN film. The fabricated laser is having a single-mode lasing with a small FWHM of 0.10 nm and a beam divergence of 1.5 degree. The lasing action can be achieved with a small structure with a side length of only 8 μm. Also, wavelength control of the lasing is achieved by varying the period and temperature. This work provides a new strategy to design compact UV lasers with high performance.