Hark! Group demonstrates first heralded single photon source made from silicon

Jun 28, 2012
Illustration of the process of photon pair generation, in which input pump photons spontaneously generate special pairs of new photons that emerge at precisely the same time, with one at a slightly lower frequency and the other a slightly higher frequency, after which heralding occurs. Credit: Srinivasan, Davanco/NIST

(Phys.org) -- In an important step towards more practical quantum information processing, researchers from the National Institute of Standards and Technology (NIST), the University of California, San Diego; and the Politecnico di Milano in Milan, Italy, have demonstrated the first heralded single photon source made from silicon. This source complements two other recently developed silicon-based technologies—interferometers for manipulating the entanglement of photons and single photon detectors—needed to build a quantum optical circuit or a secure quantum communication system.

The line between “interesting” and practical in advanced electronics and optics often comes down to making the new device compatible with existing technology. According to NIST scientist Kartik Srinivasan, the new 0.5 mm x 0.05 mm-sized heralded generator meshes with existing technology in three important ways: it operates at room temperature; it produces photons compatible with existing telecommunications systems (wavelengths of about 1550 nanometers); and it’s in silicon, and so can be built using standard, scalable fabrication techniques.

A “heralded” photon is one of a pair whose existence is announced by the detection of its partner—the “herald” photon. To get heralded single photons, the group built upon a technique previously demonstrated in called photon pair generation.

In photon pair generation, a laser pumps photons into a material whose properties cause two incoming pump photons to spontaneously generate a new pair of frequency-shifted photons. However, while these new photons emerge at precisely the same time, it is impossible to know when that will occur.

“Detecting one of these photons, therefore, lets us know to look for its partner,” says Srinivasan. “While there are a number of applications for photon pairs, heralded pairs will sometimes be needed, for example, to trigger the storage of information in future quantum-based computer memories.”

According to Srinivasan, the group’s silicon-based device efficiently produced pairs of single photons, and their experiment clearly demonstrated they could herald the presence of one photon by the detection of the other.

While the new device is a step forward, it is not yet practical, according to co-author Professor Shayan Mookherjea at UC San Diego, because a single source is not bright enough and a number of other required functions need to be integrated onto the chip. However, putting multiple sources along with their complementary components onto a single chip—something made possible by using silicon-based technology—could supply the performance needed for practical applications.

The work was among the three finalists and received an honorable mention in the Maiman Student Paper Competition.

Explore further: Precision gas sensor could fit on a chip

Related Stories

Physicists build first single-photon router

Aug 22, 2011

(PhysOrg.com) -- By demonstrating that an artificial atom embedded in a transmission line can route a single photon from an input port to one of two output ports, physicists have built the first router working ...

Recommended for you

New filter could advance terahertz data transmission

21 hours ago

University of Utah engineers have discovered a new approach for designing filters capable of separating different frequencies in the terahertz spectrum, the next generation of communications bandwidth that ...

The super-resolution revolution

21 hours ago

Cambridge scientists are part of a resolution revolution. Building powerful instruments that shatter the physical limits of optical microscopy, they are beginning to watch molecular processes as they happen, ...

Precision gas sensor could fit on a chip

23 hours ago

Using their expertise in silicon optics, Cornell engineers have miniaturized a light source in the elusive mid-infrared (mid-IR) spectrum, effectively squeezing the capabilities of a large, tabletop laser onto a 1-millimeter ...

A new X-ray microscope for nanoscale imaging

Feb 27, 2015

Delivering the capability to image nanostructures and chemical reactions down to nanometer resolution requires a new class of x-ray microscope that can perform precision microscopy experiments using ultra-bright ...

New research signals big future for quantum radar

Feb 26, 2015

A prototype quantum radar that has the potential to detect objects which are invisible to conventional systems has been developed by an international research team led by a quantum information scientist at the University ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.