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arXiv · 1408.3996

Nonideal optical cavity structure of superconducting nanowire single photon detector

Hao Li·Weijun Zhang·Lixing You·Lu Zhang·Xiaoyan Yang·Xiaoyu Liu·Sijing Chen·Chaolin Lv·Wei Peng·Zhen Wang·Xiaoming Xie
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Abstract

Optical cavity structure has been proven to be a crucial factor for obtaining high detection efficiency in superconducting nanowire single photon detector (SNSPD). Practically, complicated fabrication processes may result in a non-ideal optical cavity structure. The cross-sectional transmission electron microscope (TEM) image of SNSPD fabricated in this study shows unexpected arc-shaped optical cavities which could have originated due to the over-etching of SiO2 layer while defining NbN nanowire. The effects of the arc-shaped optical cavity structure, such as the wavelength dependence of the optical absorption efficiency for different polarization, were analyzed by performing optical simulations using finite-difference time-domain method. The central wavelength of the device is found to exhibit a blue shift owing to the arced cavity structure. This effect is equivalent to the flat cavity with a reduced height. The results may give interesting reference for SNSPD design and fabrication.

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cond-mat.supr-conphysics.optics

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Hao Li, Weijun Zhang, Lixing You, Lu Zhang, Xiaoyan Yang, Xiaoyu Liu, Sijing Chen, Chaolin Lv, Wei Peng, Zhen Wang, Xiaoming Xie. 2014-08-18. Nonideal optical cavity structure of superconducting nanowire single photon detector. https://doi.org/10.1109/jstqe.2014.2331955

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