Laser is produced by a living cell. 13 June 2011Last updated at 01:42 By Jason Palmer Science and technology reporter, BBC News The single-cell lasers were less than 20 millionths of a metre across A single living cell has been coaxed into producing laser light, researchers report in Nature Photonics.
The technique starts by engineering a cell that can produce a light-emitting protein that was first obtained from glowing jellyfish. Flooding the resulting cells with weak blue light causes them to emit directed, green laser light. The work may have applications in improved microscope imaging and light-based therapies. Laser light differs from normal light in that it is of a narrow band of colours, with the light waves all oscillating together in synchrony. Most modern forms use carefully engineered solid materials to produce lasers in everything from supermarket scanners to DVD players to industrial robots. The pair used green fluorescent protein (GFP) as the laser's "gain medium", where light amplification takes place.
Total Internal reflection. Snell's law of Refraction. 169 years after its discovery, Doppler effect found even at molecular level. Whether they know it or not, anyone who's ever gotten a speeding ticket after zooming by a radar gun has experienced the Doppler effect – a measurable shift in the frequency of radiation based on the motion of an object, which in this case is your car doing 45 miles an hour in a 30-mph zone.
But for the first time, scientists have experimentally shown a different version of the Doppler effect at a much, much smaller level – the rotation of an individual molecule. Prior to this such an effect had been theorized, but it took a complex experiment with a synchrotron to prove it's for real. "Some of us thought of this some time ago, but it's very difficult to show experimentally," said T.
Darrah Thomas, a professor emeritus of chemistry at Oregon State University and part of an international research team that today announced its findings in Physical Review Letters. But a similar effect can be observed when something rotates as well, scientists say. Physicists move closer to efficient single-photon sources. Public release date: 16-Mar-2011 [ Print | E-mail Share ] [ Close Window ] Contact: Charles E.
Bluecblue@aip.org 301-209-3091American Institute of Physics Washington, D.C. (March 16, 2011) -- A team of physicists in the United Kingdom has taken a giant step toward realizing efficient single-photon sources, which are expected to enable much-coveted completely secure optical communications, also known as "quantum cryptography.
" Fluorescent "defect centers" in diamond act like atomic-scale light sources and are trapped in a transparent material that's large enough to be picked up manually. This makes them strong contenders for use as sources of single photons (the quantum light particle) in provably secure quantum cryptography schemes, explains J. "Defect centers could also be used as building blocks for 'solid-state quantum computers,' which would use quantum effects to solve problems that are not efficiently solvable with current computer technology," Hadden says. Silver bits channel nano light TRN 042303. Computer circuits and nanodevices are already smaller than that, and getting still smaller.
The key is figuring out how to guide near-field light, which forms a standing field rather than light's usual moving wave. Electromagnetic Radiation - The Nature of Electromagnetic Radiation. Visible light is a complex phenomenon that is classically explained with a simple model based on propagating rays and wavefronts, a concept first proposed in the late 1600s by Dutch physicist Christiaan Huygens.
Electromagnetic radiation, the larger family of wave-like phenomena to which visible light belongs (also known as radiant energy), is the primary vehicle transporting energy through the vast reaches of the universe. The mechanisms by which visible light is emitted or absorbed by substances, and how it predictably reacts under varying conditions as it travels through space and the atmosphere, form the basis of the existence of color in our universe. The term electromagnetic radiation, coined by Sir James Clerk Maxwell, is derived from the characteristic electric and magnetic properties common to all forms of this wave-like energy, as manifested by the generation of both electrical and magnetic oscillating fields as the waves propagate through space. Start Tutorial » ν = c/λ where c ν.
Jablonski Diagram - Java Tutorial. Fluorescence activity can be schematically illustrated with the classical Jablonski diagram, first proposed by Professor Alexander Jablonski in 1935 to describe absorption and emission of light.
This tutorial explores how electrons in fluorophores are excited from the ground state into higher electronic energy states and the events that occur as these excited molecules emit photons and fall back into lower energy states. To operate the tutorial, first select an absorption and emission mechanism (fluorescence, phosphorescence, or delayed fluorescence) by toggling through the choices presented in the pull-down menu. Next, click on the start button with the mouse to induce a virtual electron to absorb energy and be promoted to a higher energy level.
Basic Electromagnetic Wave Properties - Java Tutorial. Electromagnetic radiation is characterized by a broad range of wavelengths and frequencies, each associated with a specific intensity (or amplitude) and quantity of energy.
This interactive tutorial explores the relationship between frequency, wavelength, and energy, and enables the visitor to adjust the intensity of the radiation and to set the wave into motion. Electron Excitation and Emission - Java Tutorial. Electrons can absorb energy from external sources, such as lasers, arc-discharge lamps, and tungsten-halogen bulbs, and be promoted to higher energy levels.
Electromagnetic Radiation - Java Tutorial. The Physics of Light and Color. The Physics of Color and Light - Light: Particle or a Wave?