Researchers at Osaka University have developed the technology to launch light spheres at an adjustable speed, opening up new possibilities for optical and physics applications.
Although it might sound like science fiction, people have been unable to manipulate the speed of light for a long time.
In a recent study published in IEEE Communications Letters, researchers at Osaka University developed light bullets that can fly at speeds of about 10 kilometers per second.
Albert Einstein’s theory of relativity states that light travels at the same speed no matter what its source or what its direction is. It is also possible to regulate the group velocity of optical pulses.
Currently, temporal and spatial coupling of optical pulses provides the possibility of regulating the group velocity of three-dimensional, diffraction-free optical wave packets, called “light bullets,” in the absence of any optical components.
In their earlier research, it was found that when the phase front of optical pulses is deformed while keeping the pulse front unchanged, the produced Bessel-Gaussian light bullets can be regulated.
“The problem, however, is that only one particular mode of motion, for example superluminal or subluminal for velocity and accelerating or decelerating for acceleration, can be achieved in a single propagation path,” says lead researcher Zhaoyang Li.
By incorporating a deformable mirror and a spatial light modulator, the pulse front of optical signals may be deformed arbitrarily, resulting in a light bullet fired from a single direction with arbitrarily variable speed (and acceleration).
An unobstructed light projectile with a nearly programmable trajectory that brings new possibilities in a range of applications, such as free-space communications, bio-imaging, optical detection and processing, particle acceleration and manipulation, radiation generation, and many others.
See: “Optical wave-packet with nearly-programmable group velocities” by Zhaoyang Li and Junji Kawanaka, Communications Physics, (subscription required)