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Updated: Nov 23, 2025
Design, Fabrication, and Experimental Characterization of Plasmonic Photoconductive Terahertz Emitters
Published on: July 8, 2013
Terahertz Broadband Polarization Conversion for Transmitted Waves Based on Graphene Plasmon Resonances
Anqi Yu1,2, Dahai Yu3, Zhenyu Yang1
1Shanghai Key Lab of Modern Optical System, Terahertz Technology Innovation Research Institute, Terahertz Spectrum and Imaging Technology Cooperative Innovation Center, University of Shanghai for Science and Technology, 516 Jungong Road, Shanghai 200093, China.
We studied terahertz (THz) polarization conversion in metallic grating structures using plasmon excitation. Our findings reveal that plasmon resonances and Drude absorption are key, enabling high transmission and multi-broadband conversion.
Area of Science:
- Optics and Photonics
- Condensed Matter Physics
- Materials Science
Background:
- Terahertz (THz) technology requires efficient polarization control for advanced applications.
- Metallic gratings and plasmonic structures offer tunable optical properties in the THz region.
- Understanding wave interactions within layered nanostructures is crucial for device development.
Purpose of the Study:
- To investigate polarization conversion of transmitted waves in a metallic grating/plasmon-excitation layer/metallic grating structure in the THz region.
- To elucidate the physical mechanisms behind polarization conversion, including Drude background absorption and plasmon resonances.
- To explore methods for achieving multi-broadband polarization conversion by controlling plasmon modes.
Main Methods:
- Application of the harmonic oscillator model and the transfer matrix method for theoretical analysis.
- Validation of theoretical models through comparison with finite-difference-time-domain (FDTD) simulations.
- Systematic investigation of structural parameter effects on polarization conversion efficiency and bandwidth.
Main Results:
- Excellent agreement between theoretical calculations and FDTD simulations.
- Identification of Drude background absorption and plasmon resonances as primary drivers of polarization conversion.
- Observation of near-zero transmission at specific grating-dielectric distances due to destructive interference, suppressing plasmon resonances.
- Achieved transmission levels exceeding 80% away from these suppression points.
- Demonstrated multi-broadband polarization conversion by exciting plasmon modes between transmission zeros.
Conclusions:
- The proposed metallic grating structure effectively controls THz wave polarization.
- Electron density and excitation efficiency are critical for the bandwidth of polarization conversion.
- Scattering rate primarily influences the rate of polarization conversion.
- The study provides a pathway for designing advanced THz polarization converters with tunable multi-broadband characteristics.
