photons tagged posts

This is an infographic explaining the fact that 10 trillionths of a suntan comes from beyond our galaxy. Credit: ICRAR/Dan Hutton

Lie on the beach this summer and your body will be bombarded by about sextillion photons of light per second.Most of these photons, originate from the Sun but a very small fraction have travelled across the Universe for billions of years before ending their existence when they collide with your skin. Astronomers have now accurately measured the light hitting Earth from outside our galaxy over a very broad wavelength range. The research looked at photons whose wavelengths vary from a fraction of a micron (damaging) to millimetres (harmless).

But radiation from outside the galaxy constitutes only ten trillionths of your suntan, so there is no immediate need for al...

Image of one of the graphene-based devices Xu and colleagues worked with. Credit: Lei Wang

In traditional light-harvesting methods, energy from 1 photon only excites 1 electron or none depending on the absorber’s energy gap. The remaining energy is lost as heat. But a new article describe an approach to coax photons into stimulating multiple electrons. Their method exploits some surprising quantum-level interactions to give one photon multiple potential electron partners.

Wu and Xu in UW’s Dept of Materials Science & Engineering and the Det of Physics, made this surprising discovery using graphene.
The researchers took a single atom layer of graphene and sandwiched it between 2 thin layers of boron-nitride. Electrons do not flow easily within boron-nitride so it is an insulator.

When the g...

Acoustic waveguide channels phonons into the optomechanical cavity, enabling the group to manipulate the motion of the suspended nanoscale beam directly. Credit: K. Balram/K. Srinivasan/NIST

A system based on this design could move and store information in next-generation computers. While Moore’s Law, the idea that the number of transistors on an integrated circuit will double every 2 years, has proven remarkably resilient, engineers will soon begin to encounter fundamental limits. As transistors shrink, heat and other factors will begin to have magnified effects in circuits. So researchers are considering designs in which electronic components interface with other physical systems that carry information such as light and sound...

3 sources of single photons: represented by a red dot at the center of the cavity, the semiconductor quantum dots (of nanometric size) is inserted in the center of the cavity, which consists of a 3 µm pillar connected to a circular frame by guides that are 1.3 µm wide. By applying electrical voltage to the cavity, the wavelength of the emitted photons can be tuned and the charge noise totally eliminated. Credit: © Niccolo Somaschi – Laboratoire de photonique et de nanostructures (CNRS)

A new ultra-bright source of single photons – 15X brighter than commonly used sources and emitting photons that are 99.5% indistinguishable from one another – has been developed by researchers from the CNRS, Université Paris Diderot, and Université Paris-Sud...