Nav: Home

Flexible optical design method for superconducting nanowire single-photon detectors

October 24, 2016

The National Institute of Information and Communications Technology (NICT, President: Dr. Masao Sakauchi) has succeeded in the development of flexible optical design method for superconducting nanowire single-photon detectors (SSPDs or SNSPDs).

This technique enables SSPDs with a broadband high detection efficiency reject a specific wavelength, and is effective for multidisciplinary applications in fields such as the quantum cryptography, fluorescence spectroscopy, and remote sensing that require high efficiency over a precise spectral range and strong signal rejection at other wavelengths.

This achievement appeared in the Scientific Reports (Nature Publishing Group) on October 24, 2016. The reported results have been partially obtained as a part of JST-SENTAN program and AMED-SENTAN program from April 2015.


We have developed SSPDs on dielectric multilayers and their optical design method, which enable us to design a variety of wavelength dependences of optical absorptance by optimizing the dielectric multilayer.

In order to achieve the high detection efficiency in SSPDs, it is crucial to optimize the optical absorptance for a target wavelength. In the conventional SSPDs, a simple cavity structure consisting of dielectric resonant layers with a mirror layer has been used. This structure is relatively simple and can effectively achieve high absorptance at the target wavelength, and the wavelength dependencies of absorptance show a single peak structure. However, in this structure, it is difficult to realize the SSPDs with high efficiency over a carefully controlled spectral range, with rejection at other wavelengths to reduce the noises.

By adopting a new SSPD structure with dielectric multilayers, it became possible to design desired wavelength dependences of the optical absorptance. As materials of dielectric multilayer, silicon dioxide (SiO2) and titanium oxide (TiO2) were used, and the niobium nitride (NbN) superconducting nanowire was put on the dielectric multilayer. The wavelength dependences of the optical absorptance in the nanowire could be designed by optimizing the layer number and thicknesses of each layer in the dielectric multilayer. We developed the SSPDs based on the optimized design, and experimentally demonstrated that the wavelength dependences of the detection efficiency follow the calculated results well. Regarding the optical design method, in order to optimize the wavelength dependence of the absorptance effectively, we perform two-step simulation of the optical multilayer calculation and the finite element analysis.

In support of the SSPD measurements, the NICT team collaborated with Osaka University, Japan and the University of Glasgow, Scotland through the NICT internship scheme.

[Future Prospects]

The developed SSPD with the dielectric multilayer and the optical design method can be applied for wide wavelength region between ultraviolet and mid-infrared, and thus provides an important basis for development of application of SSPD to quantum cryptography, fluorescence spectroscopy, and remote sensing.

National Institute of Information and Communications Technology (NICT)

Related Quantum Cryptography Articles:

Quantum nanoscope
Researchers have studied how light can be used to 'see' the quantum nature of an electronic material.
Testing quantum field theory in a quantum simulator
Quantum field theories are often hard to verify in experiments.
Looking for the quantum frontier
Researchers have developed a new theoretical framework to identify computations that occupy the 'quantum frontier' -- the boundary at which problems become impossible for today's computers and can only be solved by a quantum computer.
Seeing the quantum future... literally
Sydney scientists have demonstrated the ability to 'see' the future of quantum systems and used that knowledge to preempt their demise, in a major achievement that could help bring the strange and powerful world of quantum technology closer to reality.
New quantum states for better quantum memories
How can quantum information be stored as long as possible?
USC quantum computing researchers reduce quantum information processing errors
USC Viterbi School of Engineering scientists found a new method to reduce the heating errors that have hindered quantum computing.
Quantum drag
An University of Iowa physicist proposes that a current in one iron magnetic sheet creates a current in a separate sheet.
Quantum satellite device tests technology for global quantum network
Researchers at the National University of Singapore and University of Strathclyde, UK, report first data from a satellite that is testing technology for a global quantum network.
Quantum computing closer as RMIT drives towards first quantum data bus
Researchers have trialled a quantum processor capable of routing quantum information from different locations in a critical breakthrough for quantum computing.
New laser technique promises super-fast and super-secure quantum cryptography
A new method of implementing an 'unbreakable' quantum cryptographic system is able to transmit information at rates more than ten times faster than previous attempts.

Related Quantum Cryptography Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Jumpstarting Creativity
Our greatest breakthroughs and triumphs have one thing in common: creativity. But how do you ignite it? And how do you rekindle it? This hour, TED speakers explore ideas on jumpstarting creativity. Guests include economist Tim Harford, producer Helen Marriage, artificial intelligence researcher Steve Engels, and behavioral scientist Marily Oppezzo.
Now Playing: Science for the People

#524 The Human Network
What does a network of humans look like and how does it work? How does information spread? How do decisions and opinions spread? What gets distorted as it moves through the network and why? This week we dig into the ins and outs of human networks with Matthew Jackson, Professor of Economics at Stanford University and author of the book "The Human Network: How Your Social Position Determines Your Power, Beliefs, and Behaviours".