- The new highly compact camera can image polarization of light in one shot, revealing how light is reflected and transmitted.
- The camera enables 3D reconstruction of an object and measures its shape, depth, and texture.
- It can be integrated with smartphones and autonomous vehicles.
Many people learn in school that light is an electromagnetic wave which can travel through the vacuum of outer space. But what most people don’t know is that it has a direction called polarization. A polarized light wave (vibrating in one plane) can be either linear, circular, or elliptical.
Polarization cannot be seen with the naked human eye (but visible to certain species of insects and shrimp). Understanding and manipulating its mechanisms is crucial for several optical application.
For instance, cameras that capture polarized light are used to identify metal stress, examine surface quality for scratches and dents, and enhance contrast for object detection.
However, the existing polarization-sensitive cameras are bulky, costly and rely on moving components, which limit the scope of their potential applications.
Recently, researchers at Harvard University came up with a highly compact, portable camera capable of imaging polarization of light in a single shot. Unlike current generation cameras that only detect color and intensity of light, the new camera reveals how light is reflected and transmitted.
This research can revolutionize vision systems. The newly developed camera can be integrated with smartphones, autonomous vehicles, onboard airplanes and satellite to analyze atmospheric chemistry. It can also be used to identify camouflaged components.
Unlocking the Powerful World Of Polarization
Polarization and its measurements are of interest in almost all area of science and imaging technology. It can enable 3D reconstruction of an object, and help us determine the object’s shape, depth, and texture. It can also distinguish natural and man-made structures, even if they are identical in shape and color.
The object in unpolarized and polarized | Courtesy of researchers
In this study, researchers took advantage of metasurfaces, tiny structures that interact with light at nanoscales (wavelength size-levels). They took all essential optics and integrated them in one, simple instrument with a metasurface.
The team analyzed the characteristics of polarized light in detail and developed a metasurface that uses subwavelength, anisotropic structures to provide tunable polarization control at visible frequencies.
The light then produces 4 pictures, each picture shows a unique polarization feature. Combined together, these images provide a complete snapshot of polarization at each pixel.
This new device is no more complicated than a smartphone camera. It’s just two centimeters long, and the entire imaging system (including lens and protective case) is nearly the size of a launch box.
Researchers tested the lightweight device to detect defects in injection-molded plastics and captured various images to demonstrate how effectively it visualizes the three-dimensional contours.
The findings open new avenues for camera technology with exceptional compactness, enabling applications in machine vision, facial recognition, remote sensing, and atmospheric science.