Low-threshold near-infrared lasing at room temperature using low-toxicity Ag2Se quantum dots
Low-threshold near-infrared lasing at room temperature using low-toxicity Ag2Se quantum dots
复制标题
使用低毒性 Ag2Se 量子点在室温下产生低阈值近红外激光
DOI：
10.1039/d0nr05098a
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发表时间：
2020-11-14
期刊：
影响因子：
6.7
通讯作者：
Jia, Yunzhe
中科院分区：
文献类型：
--
作者：
Liao, Chen;Tang, Luping;Jia, Yunzhe
胶体近红外量子点激光器的发展一直受到铅盐量子点高简并性的阻碍。在这里，我们表明，这一挑战可以通过利用正交银硒量子点。我们证明，最低的量子化态的Ag 2Se量子点显示低，2倍的简并采用飞秒瞬态吸收（TA）光谱。光学增益阈值被评估为156 μ J cm（-2），对应于类似的1.4激子平均每个量子点。因此，Ag_2Se量子点薄膜的放大自发辐射（ASE）阈值低至183 μ J·cm ~（-2）。通过可变条纹长度（VSL）测量观察到薄膜的大模态增益（类似于470 cm（-1））。我们利用量子点的低阈值增益来产生微激光器，其在室温下具有单模近红外发射和163 μ J cm（-2）的低阈值。此外，Ag_2Se量子点的细胞毒性是显著可忽略的。我们的工作是朝着环境友好的近红外量子点激光器迈出的重要一步。
The development of colloidal near-infrared quantum dot (QD) lasers has been hindered by the high state degeneracy of lead salt QDs. Here, we show that this challenge can be addressed by utilizing orthorhombic Ag2Se QDs. We demonstrate that the lowest quantized states of Ag2Se QDs display a low, 2-fold degeneracy by employing femtosecond transient absorption (TA) spectroscopy. The optical gain threshold is evaluated to be 156 mu J cm(-2), corresponding to similar to 1.4 excitons per QD on average. Consequently, the amplified spontaneous emission (ASE) threshold of Ag2Se QD films is as low as 183 mu J cm(-2). A large modal gain (similar to 470 cm(-1)) of the film is observed by variable stripe length (VSL) measurements. We leverage the low-threshold gain of the QDs to produce microlasers that exhibit single-mode near-infrared emission and a low threshold of 163 mu J cm(-2) at room temperature. In addition, the cytotoxicity of Ag2Se QDs is remarkably negligible. Our work represents a significant step toward environmental-friendly near-infrared QD lasers.