Smallest LASER ever

Nanolaser: Image shows the nanolaser design: a gold core surrounded by a glasslike shell filled with green dye
Nanolaser: Image shows the nanolaser design: a gold core surrounded by a glasslike shell filled with green dyeCourtesy Birck Nanotechnology Center, Purdue University

Lasers, now used in CD and DVD players and to read prices at the checkout counter, were first developed about fifty years ago. They work by resonating light between two reflectors. They cannot be made smaller than half a wavelength of light, though (about 200 nanometers).


Researchers have now figured a way to force a sphere of only 44 nanometers to emit laser light (more than 1 million could fit inside a red blood cell). These nano-lasers are called spasers which stands for "surface plasmon amplification by stimulated emission of radiation".
When light is pumped onto the sphere, the surface coating generates a form of radiation called surface plasmons.

To act like lasers, they require a "feedback system" that causes the surface plasmons to oscillate back and forth so that they gain power and can be emitted as light.Plasmon resonances are capable of squeezing optical frequency oscillations into a nanoscopic cavity to enable a true nanolaser
Purdue University

Nanophotonics and nanoplasmonics

This new area of technology sometimes called nanophotonics or nanoplasmonics will enable better microscopes, smaller computer memories, faster computer circuits that use light instead of electrons, and many more yet to be imagined applications.

Read the research papers

This current work on spasers is published in the journal Nature: Applied physics: Lasers go nano
Demonstration of a spaser-based nanolaser

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