Wu Mengfei, Ha Son Tung, Shendre Sushant, Durmusoglu Emek G, Koh Weon-Kyu, Abujetas Diego R, Sánchez-Gil José A, Paniagua-Domínguez Ramón, Demir Hilmi Volkan, Kuznetsov Arseniy I
Institute of Materials Research and Engineering, A*STAR (Agency for Science, Technology and Research), Singapore 138634, Singapore.
LUMINOUS! Centre of Excellence for Semiconductor Lighting and Displays, Nanyang Technological University, Singapore 639798, Singapore.
Nano Lett. 2020 Aug 12;20(8):6005-6011. doi: 10.1021/acs.nanolett.0c01975. Epub 2020 Jul 8.
Solid-state room-temperature lasing with tunability in a wide range of wavelengths is desirable for many applications. To achieve this, besides an efficient gain material with a tunable emission wavelength, a high quality-factor optical cavity is essential. Here, we combine a film of colloidal CdSe/CdZnS core-shell nanoplatelets with square arrays of nanocylinders made of titanium dioxide to achieve optically pumped lasing at visible wavelengths and room temperature. The all-dielectric arrays support bound states in the continuum (BICs), which result from lattice-mediated Mie resonances and boast infinite quality factors in theory. In particular, we demonstrate lasing from a BIC that originates from out-of-plane magnetic dipoles oscillating in phase. By adjusting the diameter of the cylinders, we tune the lasing wavelength across the gain bandwidth of the nanoplatelets. The spectral tunability of both the cavity resonance and nanoplatelet gain, together with efficient light confinement in BICs, promises low-threshold lasing with wide selectivity in wavelengths.
对于许多应用而言，固态室温激光在很宽的波长范围内具有可调谐性是很理想的。要实现这一点，除了具有可调谐发射波长的高效增益材料外，高品质因数的光学腔也是必不可少的。在此，我们将胶体CdSe/CdZnS核壳纳米片薄膜与由二氧化钛制成的纳米圆柱方形阵列相结合，以实现可见光波长和室温下的光泵浦激光发射。全介质阵列支持连续统中的束缚态（BICs），这是由晶格介导的米氏共振产生的，理论上具有无限的品质因数。特别地，我们展示了来自一个由面外磁偶极子同相振荡产生的BIC的激光发射。通过调整圆柱的直径，我们在纳米片的增益带宽内调谐激光波长。腔共振和纳米片增益的光谱可调谐性，以及BICs中高效的光限制，有望实现低阈值激光发射且具有宽波长选择性。
