Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Nano Letters

Nanoscale Gap-Plasmon-Enhanced Superconducting Photon Detectors at Single-Photon Level

Jingwei Yang, Tzu-Yu Peng, Daniel D. A. Clarke, Frank Bello, Jia‐Wern Chen, Hao-Chen Yeh, Wei-Ren Syong, Chi‐Te Liang, Ortwin G. Hess, Yu‐Jung Lu

Published Oct 31, 2023• 12 citations
Publisher

Abstract

With a growing demand for detecting light at the single-photon level in various fields, researchers are focused on optimizing the performance of superconducting single-photon detectors (SSPDs) by using multiple approaches. However, input light coupling for visible light has remained a challenge in the development of efficient SSPDs. To overcome these limitations, we developed a novel system that integrates NbN superconducting microwire photon detectors (SMPDs) with gap-plasmon resonators to improve the photon detection efficiency to 98% while preserving all detector performance features, such as polarization insensitivity. The plasmonic SMPDs exhibit a hot-belt effect that generates a nonlinear photoresponse in the visible range operated at 9 K (∼0.64 T c ), resulting in a 233-fold increase in phonon–electron interaction factor (γ) compared to pristine SMPDs at resonance under CW illumination. These findings open up new opportunities for ultrasensitive single-photon detection in areas like quantum information processing, quantum optics, imaging, and sensing at visible wavelengths.

DOI
10.1021/acs.nanolett.3c01703

Related papers

Gap-plasmon-enhanced NbN superconducting photon detectors at single-photon level

Yu‐Jung Lu

Here, we use a novel approach to enhance the visible-light photoresponse in NbN superconducting microwire photon detectors (SMPDs) by integrating them with gap plasmon resonators (GPRs). This talk describes how we observe the plasmonic NbN SMPDs can achieve a 233-fold enhancement in the phonon-electron interaction factor (γ) compared to pristine NbN SMPDs under resonant conditions with illumination at 532 nm. The nonlinear photoresponse in the visible region is attributed to the gap-plasmon resonances that disrupt the Copper pairs that break the superconducting state to normal. In addition, an impressive detection efficiency of 98% was achieved using these plasmonic SMPDs.

Active Photonic Platforms (APP)•Oct 2, 2024•0 citations

Ultrasensitive plasmonic superconducting single-photon detectors for visible light

Yu‐Jung Lu

Single-photon detectors have been widely studied for decades because of their unique capability to resolve photon numbers, enabling many applications in quantum information technologies. Compared to other types of single-photon detectors, niobium nitride (NbN) superconducting nanowire single-photon detectors are promising candidates and are commercially available today. However, the absorption coefficient of superconducting NbN in the visible range is typically low, resulting in low quantum efficiency and low signal-to-noise ratios. In the present work, we use a novel approach to enhance the visible-light photoresponse in NbN superconducting microwire photon detectors (SMPDs) by integrating them with gap plasmon resonators (GPRs). This talk describes how we observe the plasmonic NbN SMPDs can achieve a 233-fold enhancement in the phonon-electron interaction factor (γ) compared to pristine NbN SMPDs under resonant conditions with illumination at 532 nm. The nonlinear photoresponse in the visible region is attributed to the gap-plasmon-induced heating that breaks the superconducting state to normal. Our results open new opportunities for ultrasensitive single-photon detection for quantum information processing, quantum optics, imaging, and sensing at visible wavelengths. The detailed mechanisms and possible applications will be discussed. Finally, I will discuss emerging plasmonic platforms based on transition metal nitrides and their potential applications.

Metamaterials, Metadevices, and Metasystems•Oct 4, 2023•0 citations

Design of NbN superconducting nanowire single photon detectors with enhanced infrared photon detection efficiency

Q. Wang, Jelmer J. Renema, Andreas Engel +1 more

Nanowire superconducting single-photon detectors (SSPDs) consist of a superconducting wire of nanoscale cross-section [1], typically 4×100 nm2. A current close to the device critical current renders the nanowire sensitive to single photons. SSPDs are known for their high efficiency, low jitter, low dark count rate and fast reset time. An important challenge for future application of SSPDs is to extend the useful wavelength range towards the infrared without comprising detector speed or dark count rate. To this end, we explore optical designs with wider nanowires that utilize efficient detection of single photons at the edge of the nanowire. Silicon nanowires on top of a NbN nanowire increase both the calculated total absorption and the internal detection efficiency significantly compared to a standard meandering wire geometry.

arXiv:1612.02840•Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC)•Jan 1, 2017•1 citation

Superconducting single photon detectors for ultrasensitive visible and IR detection

R. Espiau de Lamaëstre, L. Maingault, Laurent Frey +5 more

Superconducting single photons detectors (SSPDs) have emerged in recent years as a promising alternative for fast and sensitive infrared detectors working in the photon counting mode. In particular, those detectors combine very low dark count rates (below 1 Hz), high speed (above 1 GHz), photon number resolution and reasonable quantum efficiency (10% at telecom wavelengths). They already found applications in quantum cryptography systems and integrated circuit failure analysis, but could also be used as ultimate sensors in matrix configurations. We show here the optimization of SSPD fabrication and their optical metrology at CEA. SSPD are fabricated by patterning a 80 nm wide nanowire in a very thin (4 nm) NbN film on sapphire, forming a pixel of several microns size. A cryogenic all-fibered optoelectronic system has been developed and allows precise metrology of the optical performances of SSPD. When biasing near the critical current of the nanowire, we demonstrate a detection quantum efficiency of 8% at 1.55 µm, which is also found to be strongly polarization dependent. This quantum efficiency being limited by optical absorption, we propose a prism coupling based absorption enhancing structure that allows reaching 100% quantum efficiency.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Jan 22, 2009•3 citations

Recent advances in superconducting NbN single-photon detector development

Alexander A. Korneev, Alexander V. Divochiy, Yu. B. Vachtomin +14 more

Superconducting single-photon detector (SSPD) is a planar nanostructure patterned from 4-nm-thick NbN film deposited on sapphire substrate. The sensitive element of the SSPD is 100-nm-wide NbN strip. The device is operated at liquid helium temperature. Absorption of a photon leads to a local suppression of superconductivity producing subnanosecond-long voltage pulse. In infrared (at 1550 nm and longer wavelengths) SSPD outperforms avalanche photodiodes in terms of detection efficiency (DE), dark counts rate, maximum counting rate and timing jitter. Efficient single-mode fibre coupling of the SSPD enabled its usage in many applications ranging from single-photon sources research to quantum cryptography. Recently we managed to improve the SSPD performance and measured 25% detection efficiency at 1550 nm wavelength and dark counts rate of 10 s-1. We also improved photon-number resolving SSPD (PNR-SSPD) which realizes a spatial multiplexing of incident photons enabling resolving of up to 4 simultaneously absorbed photons. Another improvement is the increase of the photon absorption using a λ/4 microcavity integrated with the SSPD. And finally in our strive to increase the DE at longer wavelengths we fabricated SSPD with the strip almost twice narrower compared to the standard 100 nm and demonstrated that in middle infrared (about 3 μm wavelength) these devices have DE several times higher compared to the traditional SSPDs.

Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE•Apr 30, 2011•4 citations

Materials Driven Advancements in Superconducting Nanowire Single Photon Detectors

Sahil J. Patel

Superconducting Nanowire Single-Photon Detectors (SNSPDs) are the premier single-photon counting technology in the near-infrared regime. Operating via a photon-induced phase transition from the superconducting to the normal state, SNSPDs act as highly sensitive digital detectors that now play a critical role in quantum communication, deep-space optical communications, and direct dark matter detection. As the demand for these detectors scales, there is a pressing need to extend their performance capabilities toward longer wavelengths, larger active areas, and higher operating temperatures. However, advancing these metrics requires navigating complex physical trade-offs inherent to the detection mechanism. This thesis explores the material optimizations, novel detector architectures, and fundamental device physics required to push SNSPD technology beyond its current limits. The first thrust of this work focuses on extending SNSPD sensitivity into the mid-infrared (MIR) and far-infrared regimes. By developing a low-Tc (sub-1 K) WSi film engineered to reduce the characteristic detection energy, the threshold for long-wavelength detection is significantly lowered. Coupled with a novel detector architecture utilizing impedance-matching tapers and superconducting nanowire avalanche photon detectors (SNAPs), sensitivity is initially demonstrated at wavelengths up to 29um using a blackbody thermal source. Expanding beyond this limit, the implementation of quantum cascade lasers enables the demonstration of single-photon counting at wavelengths up to 88um, marking a major improvement over the current state of the art. To address the practical MIR detection challenges of low signal-to-noise ratio and restricted fill factors, this work also demonstrates a 1 mm x 1mm array of superconducting microwire single-photon detectors (SMSPDs) sensitive out to 3.7um, establishing a pathway for future antenna-coupled detectors. The second thrust investigates the development of micrometer-scale wires to simultaneously increase active area and operating temperature. Moving to microwire geometries raises fundamental questions regarding intrinsic detection mechanisms. Using a scanning lens setup, this work demonstrates the first direct observation of transverse coordinate effects in microwires, where the precise location of photon incidence across the wire width significantly alters the detector's slew rate and timing performance. To counteract this, new rectification schemes are introduced to produce a more uniform detection landscape. Specifically, the integration of a superconducting rail alongside the main detector is shown to successfully mitigate the transverse coordinate effect, improve timing performance, and increase the viable operating temperature of the detector. The third thrust explores the use of unconventional superconductors, namely MgB2 to achieve an appreciably higher-temperature single-photon detection pathway. This section details the distinct challenges associated with the growth and fabrication of detectors using air-sensitive materials and evaluates their long-term viability for the SNSPD platform. Ultimately, this thesis highlights the critical material and architectural parameters required to advance the field of single-photon detection. By elucidating the metrics and mechanisms that govern ideal detector performance, this work aims to broaden the understanding and future application of SNSPDs across diverse scientific disciplines. All the data presented here is my own unless otherwise mentioned.

•Aug 4, 2026•0 citations
With a growing demand for detecting light at the single-photon level in various fields, researchers are focused on optimizing the performance of superconducting single-photon detectors (SSPDs) by using multiple approaches. However, input light coupling for visible light has remained a challenge in the development of efficient SSPDs. To overcome these limitations, we developed a novel system that integrates NbN superconducting microwire photon detectors (SMPDs) with gap-plasmon resonators to improve the photon detection efficiency to 98% while preserving all detector performance features, such as polarization insensitivity. The plasmonic SMPDs exhibit a hot-belt effect that generates a nonlinear photoresponse in the visible range operated at 9 K (∼0.64 T c ), resulting in a 233-fold increase in phonon–electron interaction factor (γ) compared to pristine SMPDs at resonance under CW illumination. These findings open up new opportunities for ultrasensitive single-photon detection in areas like quantum information processing, quantum optics, imaging, and sensing at visible wavelengths.
Here, we use a novel approach to enhance the visible-light photoresponse in NbN superconducting microwire photon detectors (SMPDs) by integrating them with gap plasmon resonators (GPRs). This talk describes how we observe the plasmonic NbN SMPDs can achieve a 233-fold enhancement in the phonon-electron interaction factor (γ) compared to pristine NbN SMPDs under resonant conditions with illumination at 532 nm. The nonlinear photoresponse in the visible region is attributed to the gap-plasmon resonances that disrupt the Copper pairs that break the superconducting state to normal. In addition, an impressive detection efficiency of 98% was achieved using these plasmonic SMPDs.
Single-photon detectors have been widely studied for decades because of their unique capability to resolve photon numbers, enabling many applications in quantum information technologies. Compared to other types of single-photon detectors, niobium nitride (NbN) superconducting nanowire single-photon detectors are promising candidates and are commercially available today. However, the absorption coefficient of superconducting NbN in the visible range is typically low, resulting in low quantum efficiency and low signal-to-noise ratios. In the present work, we use a novel approach to enhance the visible-light photoresponse in NbN superconducting microwire photon detectors (SMPDs) by integrating them with gap plasmon resonators (GPRs). This talk describes how we observe the plasmonic NbN SMPDs can achieve a 233-fold enhancement in the phonon-electron interaction factor (γ) compared to pristine NbN SMPDs under resonant conditions with illumination at 532 nm. The nonlinear photoresponse in the visible region is attributed to the gap-plasmon-induced heating that breaks the superconducting state to normal. Our results open new opportunities for ultrasensitive single-photon detection for quantum information processing, quantum optics, imaging, and sensing at visible wavelengths. The detailed mechanisms and possible applications will be discussed. Finally, I will discuss emerging plasmonic platforms based on transition metal nitrides and their potential applications.
Nanowire superconducting single-photon detectors (SSPDs) consist of a superconducting wire of nanoscale cross-section [1], typically 4×100 nm2. A current close to the device critical current renders the nanowire sensitive to single photons. SSPDs are known for their high efficiency, low jitter, low dark count rate and fast reset time. An important challenge for future application of SSPDs is to extend the useful wavelength range towards the infrared without comprising detector speed or dark count rate. To this end, we explore optical designs with wider nanowires that utilize efficient detection of single photons at the edge of the nanowire. Silicon nanowires on top of a NbN nanowire increase both the calculated total absorption and the internal detection efficiency significantly compared to a standard meandering wire geometry.
Superconducting single photons detectors (SSPDs) have emerged in recent years as a promising alternative for fast and sensitive infrared detectors working in the photon counting mode. In particular, those detectors combine very low dark count rates (below 1 Hz), high speed (above 1 GHz), photon number resolution and reasonable quantum efficiency (10% at telecom wavelengths). They already found applications in quantum cryptography systems and integrated circuit failure analysis, but could also be used as ultimate sensors in matrix configurations. We show here the optimization of SSPD fabrication and their optical metrology at CEA. SSPD are fabricated by patterning a 80 nm wide nanowire in a very thin (4 nm) NbN film on sapphire, forming a pixel of several microns size. A cryogenic all-fibered optoelectronic system has been developed and allows precise metrology of the optical performances of SSPD. When biasing near the critical current of the nanowire, we demonstrate a detection quantum efficiency of 8% at 1.55 µm, which is also found to be strongly polarization dependent. This quantum efficiency being limited by optical absorption, we propose a prism coupling based absorption enhancing structure that allows reaching 100% quantum efficiency.
Superconducting single-photon detector (SSPD) is a planar nanostructure patterned from 4-nm-thick NbN film deposited on sapphire substrate. The sensitive element of the SSPD is 100-nm-wide NbN strip. The device is operated at liquid helium temperature. Absorption of a photon leads to a local suppression of superconductivity producing subnanosecond-long voltage pulse. In infrared (at 1550 nm and longer wavelengths) SSPD outperforms avalanche photodiodes in terms of detection efficiency (DE), dark counts rate, maximum counting rate and timing jitter. Efficient single-mode fibre coupling of the SSPD enabled its usage in many applications ranging from single-photon sources research to quantum cryptography. Recently we managed to improve the SSPD performance and measured 25% detection efficiency at 1550 nm wavelength and dark counts rate of 10 s-1. We also improved photon-number resolving SSPD (PNR-SSPD) which realizes a spatial multiplexing of incident photons enabling resolving of up to 4 simultaneously absorbed photons. Another improvement is the increase of the photon absorption using a λ/4 microcavity integrated with the SSPD. And finally in our strive to increase the DE at longer wavelengths we fabricated SSPD with the strip almost twice narrower compared to the standard 100 nm and demonstrated that in middle infrared (about 3 μm wavelength) these devices have DE several times higher compared to the traditional SSPDs.
Superconducting Nanowire Single-Photon Detectors (SNSPDs) are the premier single-photon counting technology in the near-infrared regime. Operating via a photon-induced phase transition from the superconducting to the normal state, SNSPDs act as highly sensitive digital detectors that now play a critical role in quantum communication, deep-space optical communications, and direct dark matter detection. As the demand for these detectors scales, there is a pressing need to extend their performance capabilities toward longer wavelengths, larger active areas, and higher operating temperatures. However, advancing these metrics requires navigating complex physical trade-offs inherent to the detection mechanism. This thesis explores the material optimizations, novel detector architectures, and fundamental device physics required to push SNSPD technology beyond its current limits. The first thrust of this work focuses on extending SNSPD sensitivity into the mid-infrared (MIR) and far-infrared regimes. By developing a low-Tc (sub-1 K) WSi film engineered to reduce the characteristic detection energy, the threshold for long-wavelength detection is significantly lowered. Coupled with a novel detector architecture utilizing impedance-matching tapers and superconducting nanowire avalanche photon detectors (SNAPs), sensitivity is initially demonstrated at wavelengths up to 29um using a blackbody thermal source. Expanding beyond this limit, the implementation of quantum cascade lasers enables the demonstration of single-photon counting at wavelengths up to 88um, marking a major improvement over the current state of the art. To address the practical MIR detection challenges of low signal-to-noise ratio and restricted fill factors, this work also demonstrates a 1 mm x 1mm array of superconducting microwire single-photon detectors (SMSPDs) sensitive out to 3.7um, establishing a pathway for future antenna-coupled detectors. The second thrust investigates the development of micrometer-scale wires to simultaneously increase active area and operating temperature. Moving to microwire geometries raises fundamental questions regarding intrinsic detection mechanisms. Using a scanning lens setup, this work demonstrates the first direct observation of transverse coordinate effects in microwires, where the precise location of photon incidence across the wire width significantly alters the detector's slew rate and timing performance. To counteract this, new rectification schemes are introduced to produce a more uniform detection landscape. Specifically, the integration of a superconducting rail alongside the main detector is shown to successfully mitigate the transverse coordinate effect, improve timing performance, and increase the viable operating temperature of the detector. The third thrust explores the use of unconventional superconductors, namely MgB2 to achieve an appreciably higher-temperature single-photon detection pathway. This section details the distinct challenges associated with the growth and fabrication of detectors using air-sensitive materials and evaluates their long-term viability for the SNSPD platform. Ultimately, this thesis highlights the critical material and architectural parameters required to advance the field of single-photon detection. By elucidating the metrics and mechanisms that govern ideal detector performance, this work aims to broaden the understanding and future application of SNSPDs across diverse scientific disciplines. All the data presented here is my own unless otherwise mentioned.