A tunable fiber-coupled optical cavity for agile enhancement of detector absorption
A tunable fiber-coupled optical cavity for agile enhancement of detector absorption
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DOI：
10.1063/1.4962456
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发表时间：
2016-09
影响因子：
3.2
通讯作者：
R. Heath;M. G. Tanner;R. Kirkwood;S. Miki;R. Warburton;R. Hadfield
中科院分区：
文献类型：
--
作者：
R. Heath;M. G. Tanner;R. Kirkwood;S. Miki;R. Warburton;R. Hadfield
使光子吸收最大化到薄有源结构中可能是光电探测器效率的限制因素。在这项工作中，光纤耦合的可调谐腔被证明，旨在实现接近统一的吸收到薄膜超导纳米线单光子探测器（SNSPD）的光子。描述并实现了一种用于在电信光纤的端部和反射衬底之间限定稳定腔的技术。腔谐振通过调谐输入波长和腔长两种方式实现。所得到的光学腔可以在100 nm的波长范围内原位调谐谐振吸收。该技术用于最大化进入背面耦合的Au镜SNSPD和正面耦合的分布式布拉格反射器腔SNSPD的单光子吸收。系统的检测效率（λ）是有限的薄膜中的缺陷，但在这两种情况下，我们证明了40%以上的裸光纤照明的λ的改善。
Maximizing photon absorption into thin active structures can be the limiting factor for photodetector efficiency. In this work, a fiber-coupled tunable cavity is demonstrated, designed to achieve close to unity absorption of photons into a thin film superconducting nanowire single photon detector (SNSPD). A technique for defining a stable cavity between the end of a telecommunications optical fiber and a reflective substrate is described and realized. Cavity resonances are demonstrated both through the tuning of input wavelength and cavity length. The resulting optical cavity can tune the resonant absorption in situ over a wavelength range of 100 nm. This technique is used to maximize the single photon absorption into both a back-side-coupled Au mirror SNSPD and a front-side-coupled distributed Bragg reflector cavity SNSPD. The system detection efficiency (SDE) is limited by imperfections in the thin films, but in both cases we demonstrate an improvement of the SDE by 40% over bare fiber illumination.