A new laser based on a swirling vortex of light has been created by physicists in the US. Dubbed a "topological-defect laser", the device could be used to create beams of light with orbital angular moment (OAM). It could also be a useful addition to lab-on-a-chip devices, where it could manipulate fluids and tiny particles.
Conventional lasers confine light by bouncing it back and forth in an optical cavity made of two opposing mirrors. Hui Cao and colleagues at Yale University and the Joint Quantum Institute at the University of Maryland have taken a new twist on this design by making an optical cavity that confines light by having it swirl around in a vortex. They made their optical cavity within a photonic crystal, which is a material containing a regular array of elements which are separated by distances on par with the wavelength of light. Light at certain wavelengths and travelling in certain directions will pass freely through a photonic crystal, whereas light not meeting these criteria will be diffracted into a new trajectory.
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