A team of researchers at the University of Central Florida has found a new class of laser beams. This class, which is called as “Spacetime Wave Packets” by the team, it seemed to defy the laws of light physics. These laser beams violate the principles of how light refracts and travels. This new study may lead to new, improved ways of optical communication and laser technologies.
Snell’s Law Violation
This new class of beams seems to have unique properties that are not shown by the other type of laser beams. As we know, light travels faster in air and slower in a denser medium like water, according to Snell’s law. For example, if you place a spoon in the glass full of water, then the spoon will appear to be broken in the water. It is since light travels at different speeds in a different medium. As denser medium-light moves slower in water and spoon appears to be broken.
Opposite to it, spacetime wave packets violates this behavior. These packets of light refract with new laws. These beams help to control the speed in different mediums. These lasers can travel without any speed difference in various mediums. Spacetime waves have even the characteristic of speeding up in denser materials.
Fermat’s Principle Violation
According to the research team, these beams not only violates the Snell’s law, but also these waves are ignoring Fermat’s principle. This principle says that “Light always travels along the shortest path possible.” According to the team, this principle also seems to be violated by these laser beams.
The team study has revealed that it can be possible that light waves can reach to different distances at the same time. Suppose we send signals to two different submarines at the same depths, but at different ranges. The sub with less distance will get the message signal first. But in contrast to this, these packets are capable of helping in reaching the signal pulses to different lengths in the same amount of time.
Spatial Light Modulator
The team at University has developed this laser beam class with the help of a device known as Spatial Light Modulator. This device helps to reorganize the energy of each pulse of light so that its properties in time and space are no longer different. It allows controlling the vibration, i.e., the speed of pulse traveling at the peak.
Although this new class seems to defy the essential laws of physics, it still follows the special relativity laws. This technology is just controlling the speed and not messing with the light wave oscillations with themselves. Hence, this technology will help in communication and laser technology improvements soon.
Research Team Comments
The principal investigator of the study, Mr. Abouraddy, says, “This new field that we’re developing is a new concept for light beams. As a result, everything we look into using these beams reveals new behavior. All the behavior we know about light takes an underlying presumption tacitly that its properties in space and time are separable. So, all we know in optics based on that. It’s a built-in assumption. But now, breaking that underlying assumption, we’re starting to see new behavior all over the place.”
Bhaduri, a team member, says, “Space-time refraction defies our expectations derived from Fermat’s principle and offers new opportunities for molding the flow of light and other wave phenomena.”
Another research member, Yessenov, says, “We believe that spacetime wave packets have more to offer, and many more interesting effects could get revel by using them.”
Abouraddy says the next steps for the research include studying the interaction of these new laser beams with devices such as laser cavities and optical fibers, in addition to applying these new insights to matter rather than to light waves.