Terahertz transmission properties of vanadium dioxide films deposited on gold grating structure with different periods

Abstract

Vanadium dioxide (VO 2 ) is a typical thermal induced phase transition material, exhibiting a transition from metallic phase at high temperature to insulating phase at low temperature, which is also accompanied by a conductivity change of over several orders of magnitude. The transition property makes VO 2 prominent to achieve an effective degree of control of terahertz (THz) wave. In this paper, composite films consisting of metal grating with different periods and VO 2 film were prepared by polymer assisted deposition method. Although the conductivity change of VO 2 films deposited on gold grating structure across phase transition was declined to about two orders of magnitude, the amplitude modulation depth of THz of the composite films can still reach a high value. Furthermore, it was found that the THz modulation depth was related with the grating period. According to theoretical simulation, the fluctuation height of VO 2 films, caused by metal grating structure during growth, can be used to regulate THz wave. These results demonstrate an economic and unsophisticated method to fabricate VO 2 films with thickness fluctuation structure and then tune the THz waves.

Thermal hysteresis in scattering by vanadium-dioxide spheres

“…During the transformation, the vanadium-vanadium atomic pairs located periodically in the monoclinic crystal separate into single atoms located periodically in the tetragonal crystal [3], the mass density increases by 1.79%, and the electrical conductivity increases by at least three orders of magnitude [1,4]. Not only is the transformation thermally reversible, its electromagnetic consequences are clearly evident in the sub-megahertz [5], megahertz [6], gigahertz [4,7], far-infrared [8,9], mid-infrared [2], near-infrared [10,11], and visible [10,12] spectral regimes. Therefore, this material is attractive for a variety of switching applications [13][14][15][16][17].…”

“…Monoclinic VO 2 is a dissipative insulator, i.e., both the real and the imaginary parts of the relative permittivity ε mono vo are positive, with Re {ε mono vo } significantly larger than Im {ε mono vo } in the visible and sub-visible spectral regimes [2][3][4][5][6][7][8][9][10][11][12]. However, tetragonal VO 2 is a dissipative insulator only when the freespace wavelength λ 0 1100 nm [12], with Re {ε tetra vo } > 0 and Im {ε tetra vo } > 0.…”