Most basic physics textbooks describe laser light in fairly simple terms: a beam travels directly from one point to another and, unless it strikes a mirror or other reflective surface, will continue traveling along an arrow-straight path, gradually expanding in size due to the wave nature of light.
These basic rules go out the window with high-intensity laser light. University of Maryland physicists have discovered that these self-focused laser pulses also generate violent swirls of optical energy that strongly resemble smoke rings.
In these donut-shaped light structures, known as “Spatiotemporal optical vortices,” the light energy flows through the inside of the ring and then loops back around the outside.
The vortices travel along with the laser pulse at the speed of light and control the energy flow around it. The light structures are ubiquitous and easily created with any powerful laser, given the right conditions.
“Conventional optical vortices have been studied since the late 1990s as a way to improve telecommunications, microscopy and other applications. These vortices allow you to control what gets illuminated and what doesn’t, by creating small structures in the light itself,” said the paper’s lead author Nihal Jhajj, a physics graduate student who conducted the research at IREAP. “The smoke ring vortices we discovered may have even broader applications than previously known optical vortices, because they are time dynamic, meaning that they move along with the beam instead of remaining stationary,” Jhajj added.