Graph of the theoretical performance of the Capasso group's new perfect absorber in very close agreement to the experimental data
Infrared reflectivity images with a spatial resolution of about 40 nm showing that the metal-insulator transition of a thin film of vanadium dioxide is not abrupt on a large size scale, but is combined with a percolation transition that complicates description of the material properties (Photo: D.N. Basov)
A more detailed plot of resistivity versus frequency for a number of temperatures clearly shows the reduction in conductivity associated with the correlation-induced reduction in electron state density (Image: D.N. Basov)
On the left appears a cartoon of the Capasso group's experimental setup, and on the right appears experimental data proving that their perfect absorber works very well indeed
Far-infrared image of a building at night (Image: Robert Gubbins/Shutterstock)
Harvard Professor of Applied Physics Federico Capasso and his collaborators have invented a nearly perfect optical absorber. By coating a piece of sapphire with an exceedingly thin (180 nm) layer of vanadium dioxide (VO2), a surface is created that absorbs 99.75 percent of infrared light with a wavelength of 11.6 micron wavelength. Such optical absorbers can be tailored to enable a wide range of applications.
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