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Items tagged with "photons"

Blue spheres representing atoms cause light, represented by red squiggly lines to scatter. A laser beam is represented in the background.
August 4, 2020

Scientists See Train of Photons in a New Light

Flashlight beams don’t clash together like lightsabers because individual units of light—photons—generally don’t interact with each other. Two beams don’t even flicker when they cross paths.

December 17, 2015

Controlling the Thermodynamics of Light

The concept of temperature is critical in describing many physical phenomena, such as the transition from one phase of matter to another.  Turn the temperature knob and interesting things can happen.  But other knobs might be just as important for studying some phenomena.  One such knob is chemical potential, a thermodynamic parameter first introduced in the nineteenth century by scientists for keeping track of potential energy absorbed or emitted by a system during chemical reactions.

September 9, 2015

JQI Physicists Show ‘Molecules’ Made of Light May Be Possible

From NIST TechBeat--It’s not lightsaber time, not yet. But a team including theoretical physicists from JQI and NIST has taken another step toward building objects out of photons, and the findings hint that weightless particles of light can be joined into a sort of “molecule” with its own peculiar force. Researchers show that two photons, depicted in this artist’s conception as waves (left and right), can be locked together at a short distance.

December 13, 2013

Ring around the resonator

Ring resonators are circular waveguides that are used as optical cavities. They look like tiny racetracks and are often fabricated from silicon. Photons can enter and exit a resonator and even move to neighboring waveguides through evanescent coupling. The micro-rings only let light waves circulate-- “resonate”-- if they have the right wavelength. This image, featured on the cover of the December 2013 issue of Nature Photonics, depicts an array of ring resonators designed to be a photonic analog to electrons experiencing quantum Hall physics. Read more to learn more about these micro-racetracks.

November 18, 2013

Optical cavity--not as painful as a trip to the dentist

Optical cavities can be made by arranging two mirrors facing each other. In this example, light bounces back and forth, forming a standing wave between the mirrors. One of the mirrors is designed to leak out a fraction of the light. Because of the boundaries created by the mirrors, the cavity will only build up light that satisfies a resonance condition--the light's wavelength must be a half-integer multiple of the cavity length. This means that cavities can be used to create narrow frequency sources. Read more to learn more about a cool research result using cavities.

November 14, 2013

Polarizing light: to divide (and sometimes conquer)

Polarization refers to the orientation of traveling waves with respect to a well-defined direction. Polarized sunglasses shield your eyes from light having certain orientations. Projectors that display images having different polarizations are used to generate the 3D effects seen in movies. In quantum information research, two different polarization states of light can make up a photonic qubit.

October 20, 2013

Topological Light

In this week’s issue of Nature Photonics scientists at the Joint Quantum Institute (*) report the first observation of topological effects for light in two dimensions, analogous to the quantum Hall effect for electrons. To accomplish this, they built a structure to guide infrared light over the surface of a room temperature, silicon-on-insulator chip.

September 30, 2013

Seeing Light in a New Light

Alexey Gorshkov, formerly of CalTech and Harvard, recently joined the JQI as a new Fellow. His research group can be found at http://groups.jqi.umd.edu/gorshkov/. This is a news item released earlier this week by Harvard University.