Interaction of Optical and EHF Waves With VO2 Nanosized Films and Particles

Abstract

In this paper, VO2 film on quartz substrate was prepared and investigated in an extremely high frequency (EHF) band 27–37 GHz. The study of EHF response of the nanosized VO2 films reveals strong anomalies in the temperature range of metal-insulator transition (MIT). The intrinsic radiation of VO2 film in the 28–32 GHz band in the vicinity of MIT was observed. Optical Raman spectra of VO2 film perforated by micron size holes arrays were studied. The micron holes and arrays show strong change of the Raman spectra at wavelength 532 nm due to the heating by laser beam. Optical properties of homogeneous VO2 nanospheres (NSs) were studied theoretically as well. The size effect on the optical properties of VO2 NSs was investigated. Transition into the metallic phase caused by heating of VO2-NSs leads to formation of localized surface plasmon resonance, which red-shifts slightly while its size increases. Increasing of NS's diameter in an insulator state leads to the appearance of a peak in the visible wavelength. The optical spectra of VO2-NS are much broader than that of Ag-NS. This is associated with the fact that a localized electric field in the form of a dipolar mode is more intensive for Ag than in the case of VO2.