Lasing with topological defects (Vol. 47 No. 1)

A new laser based on a swirling vortex of light has been created by the authors. The ‘topological-defect laser’ could be a useful addition to lab-on-a-chip devices, where it could manipulate fluids and tiny particles. The design could also be modified to create beams of light with orbital angular momentum.

Conventional lasers confine light by bouncing it back and forth in an optical cavity made of two opposing mirrors. The authors 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.

S. Knitter, S. F. Liew, W. Xiong, M. I. Guy, G. S. Solomon and H. Cao, Topological defect lasers, J. Opt. 18, 014005 (2016)
[Abstract]