In order to continue development of smaller, more useful particle accelerators and build upon optical computing and data transmission, scientists will need to be able to better manipulate the transmission of light. Building on prior research, a team led by Bo Zhen from the Massachusetts Institute of Technology now has a better understanding of how light can be stopped and manipulated. Zhen is the lead author of the paper, which was published in the journal Physical Review Letters.
In 2013, Zhen's group developed a new material useful for trapping light that did not involve this obstruction because the waves of light were able to cancel out that effect. What's more, they found that their new technique made it very easy to trap light that is incredibly stable, which will be very important for a variety of studies and as it is adapted into use.
“People think of this [trapped state] as very delicate,” Zhen explained in a press release, “and almost impossible to realize. But it turns out it can exist in a robust way.”
In the new study, Zhen's team found that the reason their material is able to trap light so effectively is due to the specific way it manipulates the polarity of the light. Essentially, the polarity describes the direction of the light's wavelength. With materials that trap light in other ways, such as mirrors or photonic crystals, the polarization of the light can cancel out other wavelengths and effectively obstruct beams of light, which does not make them ideal for use in practical applications.
In contrast, the material from Zhen's group forces the polarity of the light a vortex-like shape, kind of like a tornado. This fixes the light into a specific point, though the beam does not obstruct the light at any point along the way, making it useful for development of a vector beam for use in miniature particle accelerators or could boost the rate at which data is transmitted through an optical cable. This could also be employed in incredibly high resolution imaging, called stimulated emission depletion microscopy.
“This work is a great example of how supposedly well-studied physical systems can contain rich and undiscovered phenomena, which can be unearthed if you dig in the right spot,” added Yidong Chong, from Nanyang Technological University in Singapore, who was not involved in the study. “It deals with photonic crystal slabs of the sort that have been extensively analyzed, both theoretically and experimentally, since the 1990s. The fact that the system is so unexotic, together with the robustness associated with topological phenomena, should give us confidence that these modes will not simply be theoretical curiosities, but can be exploited in technologies such as microlasers.”