Supercontinuum single-photon detector using
multilayer superconducting nanowires
HAO LI,
1,2,†
YONG WANG,
1,2,†
LIXING YOU,
1,2,3,
*HEQING WANG,
1,2
HUI ZHOU,
1,3
PENG HU,
1,2,3
WEIJUN ZHANG,
1,2
XIAOYU LIU,
1,2
XIAOYAN YANG,
1,2
LU ZHANG,
1,2
ZHEN WANG,
1,2
AND XIAOMING XIE
1,2
1
State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of
Sciences (CAS), Shanghai 200050, China
2
CAS Center for Excellence in Superconducting Electronics, Shanghai 200050, China
3
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
*Corresponding author: lxyou@mail.sim.ac.cn
Received 13 August 2019; revised 12 October 2019; accepted 17 October 2019; posted 18 October 2019 (Doc. ID 375337);
published 20 November 2019
High-efficiency superconducting nanowire single-photon detectors (SNSPDs), which have numerous applications
in quantum information systems, function by using the optical cavity and the ultrasensitive photon response of
their ultra-thin superconducting nanowires. However, the wideband response of superconducting nanowires is
limited due to the resonance of the traditional optical cavity. Here, we report on a supercontinuum SNSPD that
can efficiently detect single photons over an ultra-broad spectral range from visible to mid-infrared light. Our
detection approach relies on using multiple cavities with well-separated absorbed resonances formed by fabricat-
ing multilayer superconducting nanowires on metallic mirrors with silica acting as spacer layers. Thus, we are able
to extend the absorption spectral bandwidth while maintaining considerable efficiency, as opposed to a conven-
tional single-layer SNSPD. Our calculations show that the proposed supercontinuum SNSPD exhibits an ex-
tended absorption bandwid th with increased nanowire layers. Its absorption efficiency is greater than 70%
over the entire range from 400 to 2500 nm (or 400 to 3000 nm), when using two-layer (or three-layer) nanowires.
As a proof of principle, the SNSPD with bilayer nanowires is fabricated based on the proposed detector archi-
tecture with simplified geometrical parameters. The detector achieves broadband detection efficiency over 60%
from 950 to 1650 nm. This type of detector may replace multiple narrow band detectors in a system and find uses
in the emerging and rapidly advancing field of atomic and molecular broadband spectroscopy.
© 2019 Chinese
Laser Press
https://doi.org/10.1364/PRJ.7.001425
1. INTRODUCTION
Single-photon detection with quantum-limit sensitivity is a
key-enabling technology applied extensively in modern physics,
chemistry, biology, and astronomy. Among these, the rapidly
advancing quantum information science represented by quan-
tum teleportation and quantum computation in the past dec-
ades, has largely motivated the development of single-photon
detectors (SPDs). Conventional semiconducting SPDs, such as
avalanche photodiodes and photomultiplier tubes, are widely
used for visible light detection but suffer from humble perfor-
mance in detecting near-infrared photons and beyond. In con-
trast, a superconducting material with an energy gap of several
meV, which is almost 1000 times smaller than the bandgap
energy of conventional semiconductors, would allow detecting
single photons with high efficiency in, but not limited to, the
ultraviolet to mid-infrared range [1].
The first superconducting nanowire SPD (SNSPD) demon-
strated low detection efficiency due to the limited optical
absorption capability of the nanowire [2]. The introduction
of optical cavities by fabricating mirror structures in
SNSPDs significantly improved their performance [3–7] and
led to high detection efficiency close to unity [8–10]. Along
with the understanding of the detection mechanism and the
improved fabrication and readout techniques, SNSPDs now
exhibit considerable advantages over semiconductor SPDs in
the performance metrics of detection efficiency, dark count
rate, timing jitter, and counting rate, enabling numerous appli-
cations such as in lunar–ground laser communication [11], de-
tection loophole-free local realism testing [12], and quantum
random number generation [13]. Meanwhile, the applications
of SNSPDs were widely extended from ultraviolet to mid-
infrared single-photon detection, such as fluorescence detection
from trapped ions [14], satellite laser ranging [15,16], singlet
oxygen luminescence detection [17], and mid-infrared fluores-
cence in molecular science [18]. These applications and their
associated detectors made full use of the high sensitivity and the
Research Article
Vol. 7, No. 12 / December 2019 / Photonics Research 1425
2327-9125/19/121425-07 Journal © 2019 Chinese Laser Press