Polarized Light Invisibility Technology

Researchers have resolved a longstanding mystery concerning exactly how a few fish seem to disappear from predators outdoors waters of the sea, a discovery that could assist materials researchers and also military technologists develop more efficient techniques of ocean camouflage.

In a Science paper published, a group led by researchers at the University of Texas at Austin reads that particular fish use tiny particles called platelets in their skin cells to reflect polarized light, which permits the fish to seem like they disappear from their predators. Polarized light is composed of light waves traveling in the same plane, such as the brilliant glow you occasionally see when sunlight reflects off the water.

In the study two ocean fish, the big-eyed scad and the lookdown have fine-tuned a method of avoiding predators by hiding in light. Elements in their silvery skin render them nearly impossible to see. The U.S. Navy funded the study as part of an effort understand how fish do this, and how it could be used to the navy's advantage.

Underwater, light often tends to be polarized. Lots of fish and even sophisticated modern satellites have the ability to detect variations in such polarized light. Molly Cummings, a part of the research team, shared that fish have reached the point in their evolution where they can detect polarized light, and the study suggests that they may have also developed the ability to hide in polarized light. The team hopes to investigate how and give the process human and military applications.

Polarized light is not uniform but the fish in the study were able to use them to their advantage. Many fish-and sophisticated modern satellites-have the ability to detect variations in such polarized light.
The ability of fish to reflect polarised light may also be applied in human camouflage, according to Dr. Cummings, a scientists from City College of New York, Texas A&M University, and other organizations to develop a computerized revolving platform that would hold the fish in position in the water while a polarimeter took constant measurements.

The US Navy has been looking for ways to travel in open ocean concealed, so this study is of great importance to the military. In previous studies, the researchers showed in the laboratory that a fish called the lockdown was able to adjust the polarized light to its advantage.

The new study, performed at sea, revealed that lookdowns and various other fish that reside in the open sea camouflage themselves in this manner. Parrish Brady, a collaborator with Cummings and lead writer on the brand-new study, built a video polarimeter that can tape-record polarized light in real time, permitting the researchers to essentially see the polarized light as fish do.