We introduce a 3-step method to optimise a nanostructured photodetector for infrared sensing through non degenerated two-photon absorption (NDTPA). First, the nanostructure is designed to tailor the distribution and concentration of both pump and signal intensities within the absorbing layer, thus leading to a gain in two-photon absorption. Second, the issue of the competition between NDTPA and other sub-bandgap transitions is tackled with a new figure of merit to favor as much as possible NDTPA while minimising other absorption processes. Third, a refined computation of the gain and the figure of merit is done to consider focused beams. Finally, two scenarios based on low power infrared photodetection are investigated to illustrate the flexibility and adaptibility of the method. It is shown that the gain is up to 7 times higher and the figure of merit is up to 20 times higher compared to the literature.

中文翻译：

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纳米结构双光子吸收光电探测器的优化方法

我们介绍了一种三步法，通过非简并双光子吸收 (NDTPA) 优化用于红外传感的纳米结构光电探测器。首先，纳米结构旨在调整吸收层内泵浦强度和信号强度的分布和浓度，从而获得双光子吸收的增益。其次，NDTPA 和其他子带隙跃迁之间的竞争问题通过新的品质因数得到解决，以支持尽可能多的 NDTPA，同时最小化其他吸收过程。第三，对增益和品质因数进行精细计算以考虑聚焦光束。最后，研究了基于低功率红外光电探测的两种场景，以说明该方法的灵活性和适应性。