Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NIST photon detectors have record efficiency

03.06.2005


Sensors that detect and count single photons, the smallest quantities of light, with 88 percent efficiency have been demonstrated by physicists at the National Institute of Standard and Technology (NIST). This record efficiency is an important step toward making reliable single photon detectors for use in practical quantum cryptography systems, the most secure method known for ensuring the privacy of a communications channel.


The four yellow squares in the center of this micrograph are NIST single photon detectors. The top two detectors are 25 by 25 micrometers. The bottom two detectors are 50 by 50 micrometers. The detectors operate with a record 88 percent efficiency. Credit: NIST



Described in the June issue of Physical Review A, Rapid Communications,* the NIST detectors are composed of a small square of tungsten film, 25 by 25 micrometers and 20 nanometers thick, chilled to about 110 milliKelvin, the transition temperature between normal conductivity and superconductivity. When a fiber-optic line delivers a photon to the tungsten film, the temperature rises and results in an increase in electrical resistance. The change in temperature is proportional to the photon energy, allowing the sensor to determine the number of photons in a pulse of monochromatic light.

This type of detector typically has limited efficiency because some photons are reflected from the front surface and others are transmitted all the way through the tungsten. NIST scientists more than quadrupled the detection efficiency over the past two years by depositing the tungsten over a metallic mirror and topping it with an anti-reflective coating, to enable absorption of more light in the tungsten layer.


The NIST sensors operate at the wavelength of near-infrared light used for fiber-optic communications and produce negligible false (or dark) counts. Simulations indicate it should be possible to increase the efficiency well above 99 percent at any wavelength in the ultraviolet to near-infrared frequency range, by building an optical structure with more layers and finer control over layer thickness, according to the paper.

Quantum communications and cryptography systems use the quantum properties of photons to represent 1s and 0s. The NIST sensors could be used as receivers for quantum communications systems, calibration tools for single photon sources, and evaluation tools for testing system security. They also could be used to study the performance of ultralow light optical systems and to test the principles of quantum physics. The work is supported by the Director of Central Intelligence postdoctoral program and the Advanced Research and Development Activity.

Laura Ost | EurekAlert!
Further information:
http://www.nist.gov

More articles from Physics and Astronomy:

nachricht Scientists reach back in time to discover some of the most power-packed galaxies
28.02.2017 | Clemson University

nachricht From rocks in Colorado, evidence of a 'chaotic solar system'
23.02.2017 | University of Wisconsin-Madison

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Safe glide at total engine failure with ELA-inside

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded after a glide flight with an Airbus A320 in ditching on the Hudson River. All 155 people on board were saved.

On January 15, 2009, Chesley B. Sullenberger was celebrated world-wide: after the two engines had failed due to bird strike, he and his flight crew succeeded...

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Scientists reach back in time to discover some of the most power-packed galaxies

28.02.2017 | Physics and Astronomy

Nano 'sandwich' offers unique properties

28.02.2017 | Materials Sciences

Light beam replaces blood test during heart surgery

28.02.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>