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.

中文翻译：

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通过连续体中的Mie共振束缚态在胶体纳米血小板中的室温发射。

在许多波长中具有可调性的固态室温激光是合乎需要的。为此，除了具有可调节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。在这里，我们将胶体CdSe / CdZnS核壳纳米片膜与由二氧化钛制成的纳米圆柱体的方阵相结合，以实现在可见波长和室温下的光泵浦激光。全电介质阵列支持连续体（BIC）中的束缚态，这是晶格介导的Mie共振产生的，并且在理论上具有无限的品质因数。特别是，我们展示了来自BIC的激光发射，该BIC发射自同相振荡的面外磁偶极子。通过调整气缸的直径，我们在纳米血小板的增益带宽上调整激光波长。腔共振和纳米血小板增益的光谱可调性，以及BIC中有效的光限制，保证了低阈值激光发射，并具有很宽的波长选择性。