Thermal image encryption obtained with a SiO2 space-variant subwavelength grating supporting surface phonon-polaritons.
Space-variant partially polarized thermal emission is investigated. We show that by coupling surface phonon-polaritons to a propagating field, large anisotropy of the emissivity is obtained within a narrow spectral range. We experimentally demonstrate this effect by fabricating a space-variant subwavelength grating on a SiO2 substrate to encrypt an image in the polarization state of a thermal radiation field.
Dahan
Nir
N
Optical Engineering Laboratory, Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa.
Niv
Avi
A
Biener
Gabriel
G
Kleiner
Vladimir
V
Hasman
Erez
E