Versatile polarization manipulation in vanadium dioxide-integrated terahertz metamaterial

Abstract

Broadband and switchable versatile polarization metamaterial is crucial in the applications of imaging, sensing and communication, especially in the terahertz frequency. Here, we investigated versatile polarization manipulation in a hybrid terahertz metamaterial with bilayer rectangular rods and a complementary vanadium dioxide (VO2) layer. The VO2 phase transition enables a flexible switching from dual-band asymmetric transmission to dual-band reflective half-wave plate. The full width half maximum (FWHM) bandwidths of dual-band asymmetric transmission are 0.77 and 0.21 THz, respectively. The polarization conversion ratio (PCR) of the reflective metamaterial is over 0.9 in the frequency ranges of 1.01-1.17 THz and 1.47-1.95 THz. Angular dependences of multiple polarization properties are studied. The proposed switchable polarization metamaterial is important to the development of multifunctional polarization devices and multichannel polarization detection.

Difunctional terahertz metasurface with switchable polarization conversion and absorption by VO2 and photosensitive silicon

“…In the simulation, the permittivity of VO 2 e(o) is calculated by applying the equation from the Drude model: 23 eðoÞ…”

“…where s 0 = 3 Â 10 5 S m À1 and o P (s 0 ) = 1.4 Â 10 15 rad s À1 . 23 Both original VO 2 conductivities can be set to s = 1 S m À1 (dielectric state) and s = 2 Â 10 5 S m À1 (metallic state). 23 When studying the relationship between the incident and transmitted waves, the Jones matrix will be used and expressed as follows: 24 Lorentz reciprocal theorem, the Jones matrix of a THz wave incident from the bottom is shown as: 25…”

“…In the simulation, the permittivity of VO 2 ε ( ω ) is calculated by applying the equation from the Drude model: 23 where ε ∞ = 12 is the dielectric constant at the infinite frequency, and γ = 5.75 × 10 13 rad s −1 refers to the crash frequency. ω P ( σ ) is the equivalent frequency that would be expressed by the function of conductivity σ as follows:where σ 0 = 3 × 10 5 S m −1 and ω P ( σ 0 ) = 1.4 × 10 15 rad s −1 .…”

“…ω P ( σ ) is the equivalent frequency that would be expressed by the function of conductivity σ as follows:where σ 0 = 3 × 10 5 S m −1 and ω P ( σ 0 ) = 1.4 × 10 15 rad s −1 . 23 Both original VO 2 conductivities can be set to σ = 1 S m −1 (dielectric state) and σ = 2 × 10 5 S m −1 (metallic state). 23 When studying the relationship between the incident and transmitted waves, the Jones matrix will be used and expressed as follows: 24 where subscripts x and y indicate the x -polarization and y -polarization directions in THz waves, respectively.…”

“…23 Both original VO 2 conductivities can be set to σ = 1 S m −1 (dielectric state) and σ = 2 × 10 5 S m −1 (metallic state). 23 When studying the relationship between the incident and transmitted waves, the Jones matrix will be used and expressed as follows: 24 where subscripts x and y indicate the x -polarization and y -polarization directions in THz waves, respectively. T and t indicate the transfer matrix and the transmission coefficient, respectively.…”