New Kind of Laser Uses Tiny Particle Clumps To Generate Light

A new kind of laser uses tiny moving particles to produce beams of light. The laser is more programmable than standard lasers and the approach could be used to create visual displays that are sharp from all angles. New Scientist reports: Conventional lasers repeatedly bounce light between two mirrors until it becomes bright and focused. Riccardo Sapienza at Imperial College London and his colleagues have built a laser that uses particles that can arrange themselves to carry out a similar process. The new type of laser first requires the use of green light from a traditional laser. The researchers shine this light into a small glass box filled with a liquid solution containing particles of titanium oxide and silicon oxide. This warms up the silicon oxide particles and causes the titanium oxide particles to clump around them. The green light then bounces between particles in the clump -- similarly to how light bounces between mirrors in conventional lasers -- until the clump itself starts to emit a laser beam, now in the color red. By nudging the particles into different positions with the green light, the team can program the properties of the light emitted by the laser, such as where in the device it originates from and how pure its color is. By comparison, conventional lasers can't be adjusted after manufacturing. The findings have been published in the journal Nature Physics.

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