Optical phonons assisted infrared absorption in VO2 based bolometer

Optical phonons assisted infrared absorption in VO2 based bolometer is demonstrated to be free, low, or over damping oscillation over different spectral ranges depending on the passivation thickness. In particular, it will become saturated due to the over damping oscillation in the spectral range corresponding to the absorption bands from strong phonon vibrations. The device reaches a peak absorbance of 99.9% at wavelength of 9.1 mu m and shows a broadband absorption, independent of metal-insulator transition and radiation incident angle up to 30 degrees in the long wavelength (8-14 mu m) infrared region. (c) 2007 American Institute of Physics.