State Key Laboratory of Luminescent Materials and Devices, School of Materials Science and Engineering, South China University of Technology, Wushan Road 381, Guangzhou, 510641, P. R. China.
School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu, Sichuan, 610054, P. R. China.
Adv Mater. 2018 Aug;30(31):e1801021. doi: 10.1002/adma.201801021. Epub 2018 Jun 19.
Pulsed lasers operating in the mid-infrared (3-25 µm) are increasingly becoming the light source of choice for a wide range of industrial and scientific applications such as spectroscopy, biomedical research, sensing, imaging, and communication. Up to now, one of the factors limiting the mid-infrared pulsed lasers is the lack of optical switch with a capability of pulse generation, especially for those with wideband response. Here, a semiconductor material of bismuth oxyselenide (Bi O Se) with a facile processibility, constituting an ultrabroadband saturable absorber for the mid-infrared (actually from the near-infrared to mid-infrared: 0.8-5.0 µm) is exhibited. Significantly, it is found that the optical response is associated with a strong nonlinear character, showing picosecond response time and response amplitude up to ≈330.1% at 5.0 µm. Combined with facile processibility and low cost, these solution-processed Bi O Se materials may offer a scalable and printable mid-infrared optical switch to open up the long-sought parameter space which is crucial for the exploitation of compact and high-performance mid-infrared pulsed laser sources.
工作在中红外波段（3-25μm）的脉冲激光器正日益成为各种工业和科学应用的首选光源，如光谱学、生物医学研究、传感、成像和通信。到目前为止，限制中红外脉冲激光器发展的因素之一是缺乏具有脉冲产生能力的光开关，特别是对于那些具有宽带响应的光开关。在这里，展示了一种具有易加工性的半导体材料——氧化铋硒（Bi O Se），它构成了一个超宽带可饱和吸收体，可用于中红外（实际上是从近红外到中红外：0.8-5.0μm）。值得注意的是，人们发现光学响应与强烈的非线性特性有关，在 5.0μm 处表现出皮秒级的响应时间和高达 ≈330.1%的响应幅度。结合易加工性和低成本，这些溶液处理的 Bi O Se 材料可能为可扩展和可打印的中红外光开关提供了一种方案，开辟了人们长期寻求的关键参数空间，这对于开发紧凑、高性能的中红外脉冲激光源至关重要。
