Abstract-Active thermal modulation of electromagnetically induced transparency at terahertz frequencies

 

Wentao Zhang, Hongyang Li, Shan Yin, Wei Huang, Xintong Shi, Yuting Zhang, 

https://www.spiedigitallibrary.org/journals/optical-engineering/volume-59/issue-12/127111/Active-thermal-modulation-of-electromagnetically-induced-transparency-at-terahertz-frequencies/10.1117/1.OE.59.12.127111.short?SSO=1

We present thermal control of electromagnetically induced transparency (EIT) by actively modulating the dark mode in terahertz (THz) metamaterials, including a cut wire and a split-ring resonator (SRR). By integrating indium antimonide (InSb) into the SRR and increasing the temperature, the active modulation of EIT is realized. The coupling mechanism is numerically analyzed through the coupled oscillator model, and the result of fitting the EIT intensity agrees well with the simulation results when the temperature changes from 200 to 240 K. By analyzing the electric field distribution, the physical mechanism is the change in the damping rate of the dark mode resonator due to the increase in InSb temperature. Our work has practical significance in designing tunable THz functional devices.

© 2020 Society of Photo-Optical Instrumentation Engineers (SPIE) 0091-3286/2020/$28.00 © 2020 SPIE

Abstract-Adiabatic following of terahertz surface plasmon-polaritons based on tri-layered corrugated thin film coupler

Wei Huang, Shan Yin, Wentao Zhang, Kaili Wang, Yuting Zhang, Jiaguang Han

https://arxiv.org/abs/1901.08424

In this paper, we utilize coupled mode theory (CMT) to model the coupling of surface plasmon polaritons (SPPs) between tri-layered corrugated thin films (CTF) structure coupler in the terahertz region. Employing the stimulated raman adiabatic passage (STIRAP) quantum control technique, we propose a novel directional coupler based on SPPs evolution in tri-layered CTF in some curved configuration. Our calculated results show that the SPPs can be completely transferred from the input to the output CTF waveguides, and even we consider SPPs propagation loss, the transfer rate is still above 70%. The performance of our coupler is also robust that it is not sensitive to the geometry of device and wavelength of SPPs. As a result, our device can tolerate defect induced by fabrication and manipulate THz wave at broadband.

Abstract-Spoof surface plasmon polaritons in terahertz transmission through subwavelength hole arrays analyzed by coupled oscillator model

• 
  • Shan Yin
  • , Xinchao Lu
  • , Ningning Xu
  • , Shuang Wang
  • , Yiwen E.
  • , Xuecong Pan
  • , Xinlong Xu
  • , Hongyao Liu
  • , Lu Chen
  • , Weili Zhang
  •  & Li Wang

http://www.nature.com/articles/srep16440

• Both the localized resonance and excitation of spoof surface plasmon polaritons are observed in the terahertz transmission spectra of periodic subwavelength hole arrays. Analyzing with the coupled oscillator model, we find that the terahertz transmission is actually facilitated by three successive processes: the incident terahertz field first initiates the localized oscillation around each hole, and then the spoof surface plasmon polaritons are excited by the localized resonance, and finally the two resonances couple and contribute to the transmission. Tailoring the localized resonance by hole size, the coupling strength between spoof surface plasmon polaritons and localized resonances is quantitatively extracted. The hole size dependent transmittance and the coupling mechanism are further confirmed by fitting the measured spectra to a modified multi-order Fano model.