The conversion of certain parameters, such as light intensity, into electrical signals underlies the principles of operation of cameras used in smartphones, tablet computers, etc. However, all sensors based on CCD-matrices have one drawback – they work only in one rather narrow range of the light spectrum. Now, scientists have developed an alternative option, a sensor that can measure the parameters of light of virtually any range mechanically, which greatly expands its scope.
Created by scientists from the University of Oregon, it is called a “nanomechanical graphene bolometer” and its working element resembles a tiny trampoline in shape. A “trampoline” is a sheet of graphene, a material that is a form of carbon with a crystal lattice of a monatomic thickness. This graphene membrane, which has high thermal and electrical conductivity, has been given the necessary shape, and it is stretched inside the silicon base. All this is about ten times smaller than the thickness of a human hair.
When light, independent of its wavelength, falls on graphene, this material heats up very quickly at the point of incidence of light and expands, which leads to a change in the resonant frequencies of the membrane as a whole. In fact, by tracking changes in the frequency and shape of the mechanical vibrations of the graphene membrane, it is possible to establish with high enough accuracy the amount and parameters of the light that has hit the surface of the bolometer sensor.
Such a technology can ultimately be used in a wide range of applications, from astronomy to radiography, due to the ability to measure light with different wavelengths, from long-wave infrared light to short-wave x-ray. In addition to this, such a sensor remains operational both at room temperature and at temperatures up to 2000 degrees Celsius in theory.
“We hope that the device we created will enable scientists to unravel some of the secrets of our Sun, will improve the field of medical diagnostics and implement safe thermal radiography,” says Professor Benjamin Aleman, head of the scientists group, “The new technology is also capable of to help firefighters and the military see in raging flames, which in turn will save many human lives”.