Design of broadband high-efficiency superconducting-nanowire single photon detectors
Abstract
In this paper several designs to maximize the absorption efficiency of superconducting-nanowire single-photon detectors are investigated. Using a simple optical cavity consisting of a gold mirror and a SiO2 layer, the absorption efficiency can be boosted to over 97%: this result is confirmed experimentally by the realization of an NbTiN-based detector having an overall system detection efficiency of 85% at 1.31 micrometers. Calculations show that by sandwiching the nanowire between two dielectric Bragg reflectors, unity absorption (> 99.9%) could be reached at the peak wavelength for optimized structures. To achieve broadband high efficiency, a different approach is considered: a waveguide-coupled detector. The calculations performed in this work show that, by correctly dimensioning the waveguide and the nanowire, polarization-insensitive detectors absorbing more than 95% of the injected photons over a wavelength range of several hundred nm can be designed. We propose a detector design making use of GaN/AlN waveguides, since these materials allow lattice-matched epitaxial deposition of Nb(Ti)N films and are transparent on a very wide wavelength range.
Keywords
Cite
@article{arxiv.1602.06846,
title = {Design of broadband high-efficiency superconducting-nanowire single photon detectors},
author = {Luca Redaelli and Gabriele Bulgarini and Sergiy Dobrovolskiy and Sander N. Dorenbos and Val Zwiller and Eva Monroy and Jean-Michel Gérard},
journal= {arXiv preprint arXiv:1602.06846},
year = {2016}
}