Described in a new paper,* the NIST/JPL array-on-a-chip easily identifies the position of the exact detector in a multi-detector system that absorbs an incoming infrared light particle, or photon.
This NIST device, 1.5 by 3 centimeters in outer dimensions, is a prototype receiver for laser communications enabling much higher data rates than conventional systems. Superconducting detectors in the center of the small square chip register the timing and position of single particles of light.
Credit: Verma and Tomlin/NIST
That's the norm for digital photography cameras, of course, but a significant improvement in these astonishingly sensitive detectors that can register a single photon. The new device also records the signal timing, as these particular single-photon detectors have always done.
The technology could be useful in optical communications in space. Lasers can transmit only very low light levels across vast distances, so signals need to contain as much information as possible.
One solution is "pulse position modulation" in which a photon is transmitted at different times and positions to encode more than the usual one bit of information. If a light source transmitted photons slightly to the left/right and up/down, for instance, then the new NIST/JPL detector array circuit could decipher the two bits of information encoded in the spatial position of the photon. Additional bits of information could be encoded by using the arrival time of the photon.
The same NIST/JPL collaboration recently produced detector arrays for the first demonstration of two-way laser communications outside Earth's orbit using the timing version of pulse position modulation.** The new NIST/JPL paper shows how to make an even larger array of detectors for future communications systems.
The new technology uses superconducting nanowire single-photon detectors. The current design can count tens of millions of photons per second but the researchers say it could be scaled up to a system capable of counting of nearly a billion photons per second with low dark (false) counts. The key innovation enabling the latest device was NIST's 2011 introduction of a new detector material, tungsten-silicide, which boosted efficiency, the ability to generate an electrical signal for each arriving photon.*** Detector efficiency now exceeds 90 percent. Other materials are less efficient and would be more difficult to incorporate into complex circuits.
The detectors superconduct at cryogenic temperatures (about minus 270 °C or minus 454 °F), and cooling needs set a limit on wiring complexity. The NIST/JPL scheme requires only twice as many wires (2N) as the number of detectors on one side of a square array (N x N), greatly reducing cooling loads compared to a one-wire-per-detector approach while maintaining high timing accuracy. NIST researchers demonstrated the scheme for a four-detector array with four wires and are now working on a 64-detector array with 16 wires.
In the circuit, each detector is located in a specific column and row of the square array. Each detector acts like an electrical switch. When the detector is in the superconducting state, the switch is closed and the current is equally distributed among all detectors in that column. When a detector absorbs a photon, the switch opens, temporarily diverting the current to an amplifier for the affected column while reducing the signal through the affected row. As a result, the circuit generates a voltage spike in the column readout and a voltage dip in the row readout. The active detector is at the intersection of the active column and row.
The research was supported by the Defense Advanced Research Projects Agency.
V.B. Verma, R. Horansky, F. Marsili, J.A. Stern, M.D. Shaw, A.E. Lita, R.P. Mirin and S.W. Nam. A four-pixel single-photon pulse position camera fabricated from WSi superconducting nanowire single photon detectors. Applied Physics Letters 104, 051115. DOI: 10.1063/1.4864075. Posted online Feb. 4, 2014.
See Oct. 28, 2013, National Aeronautics and Space Administration news release, "Historic Demonstration Proves Laser Communication Possible," at http://www.nasa.gov/content/goddard/historic-demonstration-proves-laser-communication-possible/#.Um62W3Dkvv2.
See 2011 NIST Tech Beat article, "Key Ingredient: Change in Material Boosts Prospects of Ultrafast Single-photon Detector," at http://www.nist.gov/pml/div686/detector-063011.cfm.
Laura Ost | EurekAlert!
Donuts, math, and superdense teleportation of quantum information
29.05.2015 | University of Illinois College of Engineering
Physicists precisely measure interaction between atoms and carbon surfaces
29.05.2015 | University of Washington
Many joining and cutting processes are possible only with lasers. New technologies make it possible to manufacture metal components with hollow structures that are significantly lighter and yet just as stable as solid components. In addition, lasers can be used to combine various lightweight construction materials and steels with each other. The Fraunhofer Institute for Laser Technology ILT in Aachen is presenting a range of such solutions at the LASER World of Photonics trade fair from June 22 to 25, 2015 in Munich, Germany, (Hall A3, Stand 121).
Lightweight construction materials are popular: aluminum is used in the bodywork of cars, for example, and aircraft fuselages already consist in large part of...
Using ultrashort laser pulses, scientists in Max Planck Institute of Quantum Optics have demonstrated the emission of extreme ultraviolet radiation from thin dielectric films and have investigated the underlying mechanisms.
In 1961, only shortly after the invention of the first laser, scientists exposed silicon dioxide crystals (also known as quartz) to an intense ruby laser to...
The only professorship in Germany to date, one master's programme, one laboratory with worldwide unique equipment and the corresponding research results: The University of Würzburg is leading in the field of biofabrication.
Paul Dalton is presently the only professor of biofabrication in Germany. About a year ago, the Australian researcher relocated to the Würzburg department for...
Physicists have developed an innovative method that could enable the efficient use of nanocomponents in electronic circuits. To achieve this, they have developed a layout in which a nanocomponent is connected to two electrical conductors, which uncouple the electrical signal in a highly efficient manner. The scientists at the Department of Physics and the Swiss Nanoscience Institute at the University of Basel have published their results in the scientific journal “Nature Communications” together with their colleagues from ETH Zurich.
Electronic components are becoming smaller and smaller. Components measuring just a few nanometers – the size of around ten atoms – are already being produced...
Development and implementation of an advanced automobile parking navigation platform for parking services
To fulfill the requirements of the industry, PolyU researchers developed the Advanced Automobile Parking Navigation Platform, which includes smart devices,...
20.05.2015 | Event News
18.05.2015 | Event News
12.05.2015 | Event News
29.05.2015 | Life Sciences
29.05.2015 | Earth Sciences
29.05.2015 | Physics and Astronomy