Laboratory of Thermodynamics in Emerging Technologies, Institute of Energy Technology, Department of Mechanical and Process Engineering, ETH Zürich, CH-8092 Zürich, Switzerland.
Thomas J. Watson Sr Laboratories of Applied Physics, California Institute of Technology, Pasadena 91125, CA, USA.
Sci Rep. 2016 Nov 22;6:37564. doi: 10.1038/srep37564.
Light detection and quantification is fundamental to the functioning of a broad palette of technologies. While expensive avalanche photodiodes and superconducting bolometers are examples of detectors achieving single-photon sensitivity and time resolutions down to the picosecond range, thermoelectric-based photodetectors are much more affordable alternatives that can be used to measure substantially higher levels of light power (few kW/cm). However, in thermoelectric detectors, achieving broadband or wavelength-selective performance with high sensitivity and good temporal resolution requires careful design of the absorbing element. Here, combining the high absorptivity and low heat capacity of a nanoengineered plasmonic thin-film absorber with the robustness and linear response of a thermoelectric sensor, we present a hybrid detector for visible and near-infrared light achieving response times of the order of 100 milliseconds, almost four times shorter than the same thermoelectric device covered with a conventional absorber. Furthermore, we show an almost two times higher light-to-electricity efficiency upon replacing the conventional absorber with a plasmonic absorber. With these improvements, which are direct results of the efficiency and ultra-small thickness of the plasmonic absorber, this hybrid detector constitutes an ideal component for various medium-intensity light sensing applications requiring spectrally tailored absorption coatings with either broadband or narrowband characteristics.
光探测和量化是广泛的技术功能的基础。虽然昂贵的雪崩光电二极管和超导测辐射热仪是实现单光子灵敏度和皮秒级时间分辨率的探测器的例子，但基于热电的光电探测器是更经济实惠的选择，可以用于测量高得多的光功率（几千瓦/平方厘米）。然而，在热电探测器中，要实现宽带或波长选择性性能，同时具有高灵敏度和良好的时间分辨率，需要仔细设计吸收元件。在这里，我们将纳米工程等离子体薄膜吸收体的高吸收率和低热容量与热电传感器的坚固性和线性响应相结合，提出了一种用于可见光和近红外光的混合探测器，其响应时间约为 100 毫秒，比用传统吸收体覆盖的相同热电设备快近四倍。此外，我们发现，用等离子体吸收体代替传统吸收体，光电效率几乎提高了两倍。由于等离子体吸收体的效率和超小厚度，这些改进是直接的结果，这种混合探测器构成了各种中等强度光感测应用的理想组件，这些应用需要具有宽带或窄带特性的光谱可调吸收涂层。
