%0 Journal Article
%T Nonideal optical cavity structure of superconducting nanowire single photon detector
%A Hao Li
%A Weijun Zhang
%A Lixing You
%A Lu Zhang
%A Xiaoyan Yang
%A Xiaoyu Liu
%A Sijing Chen
%A Chaolin Lv
%A Wei Peng
%A Zhen Wang
%A Xiaoming Xie
%J Physics
%D 2014
%I arXiv
%R 10.1109/JSTQE.2014.2331955
%X 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.
%U http://arxiv.org/abs/1408.3996v1