Qian Linyong, Zhang Xin, Zhang Jiahua, Yang Zhengweiyi, Qiu Yun, Wang Kangni
Opt Lett. 2024 Sep 15;49(18):5091-5094. doi: 10.1364/OL.537421.
Bound states in the continuum (BICs) have been demonstrated as an effective mechanism to achieve high quality (Q)-factor cavities for nanolasers. However, the development of a compact BIC laser with a low threshold has remained elusive. Here, we numerically report lasing action from symmetry-protected BICs in a two-dimensional heterostructure, which consists of compound gratings with finite cells surrounded by orthogonal distributed Bragg reflectors (DBRs). The compound grating is used to excite quasi-BIC resonance with a high Q-factor, and DBRs enable light confinement and localized electric fields to enhance light-matter interaction. The nanolaser with a threshold of 16.8 µJ/cm is achieved within a footprint as small as 3.35 × 3.35 µm. By changing the phase adjusting gap or asymmetry degree, it is possible to control the lasing emission. This work reveals a new, to our knowledge, path toward compact BIC lasers with a simple scheme for applications that require a small footprint and low threshold.
连续域束缚态（BICs）已被证明是一种为纳米激光器实现高品质（Q）因子腔的有效机制。然而，开发具有低阈值的紧凑型BIC激光器仍然难以实现。在此，我们通过数值模拟报道了二维异质结构中对称保护BICs的激光作用，该异质结构由具有有限单元的复合光栅组成，周围环绕着正交分布布拉格反射器（DBR）。复合光栅用于激发具有高Q因子的准BIC共振，而DBR能够实现光限制和局部电场，以增强光与物质的相互作用。在小至3.35×3.35 µm的面积内实现了阈值为16.8 µJ/cm²的纳米激光器。通过改变相位调整间隙或不对称程度，可以控制激光发射。据我们所知，这项工作揭示了一条通往紧凑型BIC激光器的新途径，该激光器具有简单的方案，适用于需要小面积和低阈值的应用。
