Researcher achieves breakthrough in building efficient single-photon detector

Jan 25, 2013
Researcher achieves breakthrough in building efficient single-photon detector
The single-photon detector is characterized by five convincing factors: 91% detection efficiency; direct integration on chip; counting rates on a Gigahertz scale; high timing resolution and negligible dark counting rates. Credit: KIT/CFN

Ultrafast, efficient, and reliable single-photon detectors are among the most sought-after components in photonics and quantum communication, which have not yet reached maturity for practical application. Physicist Dr. Wolfram Pernice of the Karlsruhe Institute of Technology (KIT), in cooperation with colleagues at Yale University, Boston University, and Moscow State Pedagogical University, achieved the decisive breakthrough by integrating single-photon detectors with nanophotonic chips. The detector combines near-unity detection efficiency with high timing resolution and has a very low error rate. The results have been published by Nature Communications.

Without reliable detection of single photons, it is impossible to make real use of the latest advances in or quantum computation; it is like having no analog-digital converter in a conventional computer to determine whether the applied voltage stands for 0 or 1. Although a number of different single-photon detector models have been developed over the past few years, thus far, none have provided satisfactory performance.

Several new ideas and advanced developments went into the prototype developed within the "Integrated " project at the DFG Center of (CFN). The new single-, tested in the telecommunications , achieves a previously unattained detection efficiency of 91%.

The detector was realized by fabricating superconducting nanowires directly on top of a nanophotonic waveguide. This geometry can be compared to a tube that conducts light, around which a wire in a superconducting state is wound and, as such, has no electric resistivity. The nanometer-sized wire made of niobium nitride absorbs photons that propagate along the waveguide. When a photon is absorbed, superconductivity is lost, which is detected as an . The longer the tube, the higher is the detection probability. The lengths involved are in the micrometer range.

A special feature of the detector is its direct installation on the chip, which allows for it to be replicated at random. The single-photon detectors built thus far were stand-alone units, which were connected to chips with optical fibers. Arrangements of that type suffer from photons being lost in the fiber connection or being absorbed in other ways. These loss channels do not exist in the detector that is now fully embedded in a silicon photonic circuit. In addition to high detection efficiency, this gives rise to a remarkably low dark count rate. Dark counts arise when a photon is detected erroneously: for instance, because of a spontaneous emission, an alpha particle, or a spurious field. The new design also provides ultrashort timing jitter of 18 picoseconds, which is 18 times 10-12 seconds.

The novel solution also makes it possible to integrate several hundreds of these detectors on a single chip. This is a basic precondition for future use in optical quantum computers.

The detector demonstrated in this study was designed to work at wavelengths in the Telekom bandwidth. The same detector architecture can also be used for wavelengths in the range of visible light. This would allow the principle to be employed in analyses of all structures that emit little light, i.e., photons, such as single molecules or bacteria.

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More information: doi:10.1038/ncomms2307

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1.7 / 5 (6) Jan 25, 2013
Oh look, a Wineland and Haroche type of "research"! They can't mint enough medals for them all ingeniahs westernahs... God knows what hungered Chinese grad student they stole this discovery from... Scum like Edison, Marconi, Bell... Today from Asians and eastern Europeans, as yesterday from Tesla, Meucci and countless others...

What a hilarious site. It comes fully loaded, with a "rating system" for them comments even! You can give little stars to posters. (S)he loves me, (s)he loves me not... Please please... will you rate my posts high so I can sleep tight... You can use them ALL your fake accounts to give me as many stars as you can! Thank you oh thank you oh...!!

In the meantime, on planet Earth: "How Wineland & Haroche Stole My Discovery (and got 2012 PHYSICS NOBEL PRIZE for it...)":
2 / 5 (4) Jan 26, 2013
Strange but true - the human eye has been capable of detecting a single photon for almost 6000 years now. And it is still unsurpassed in its efficiency in doing that, compared to human devices.
1 / 5 (1) Jan 27, 2013
kevinrtrs mumbled implication to make a claim
Strange but true - the human eye has been capable of detecting a single photon for almost 6000 years now. And it is still unsurpassed in its efficiency in doing that, compared to human devices.
You claim humans can detect a 'single photon' then how is it cats & some birds have better vision, can they detect 'half' a photon ?

Or how about UV as some bees detect, why are humans still so flawed & can't see UV, well we can open our eyes & go blind in the process but cant actually see it, is this 'intelligent' design or a deity's stupidity so kids can go blind ?

Um, let me think kevinrtrs, what could an alternative be ?

Ever seen an orchid or other flowers in UV or IR which we are blind to ?

kevinrtrs get a grip, humans are a work in progress not in any way shape or form complete, we have so many issues, is it god's punishment for what some great^n grandma did ?

What prick or dick of a deity punishes the children of a grandma, FFS ?