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Design, Fabrication, and Experimental Characterization of Plasmonic Photoconductive Terahertz Emitters
Published on: July 8, 2013
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Electron-beam induced terahertz radiation from graded metallic grating
Optics Express
|August 5, 2014
Summary
Electron-beam excitation of graded metallic gratings generates unique terahertz (THz) radiation. This novel spoof surface plasmon polariton (spoof SPP) based THz source offers directional control and tunable frequencies.
Area of Science:
- Condensed Matter Physics
- Electromagnetism
- Photonics
Background:
- Conventional Smith-Purcell radiation theory does not explain observed phenomena in graded gratings.
- Spoof surface plasmon polaritons (spoof SPPs) are crucial for understanding THz interactions with subwavelength metallic structures.
Purpose of the Study:
- To numerically analyze electron-beam induced terahertz (THz) radiation from metallic gratings with graded depths.
- To investigate the underlying physics of THz generation and emission mechanisms in these structures.
Main Methods:
- Utilized a simplified particle-in-cell finite-difference time-domain (PIC-FDTD) numerical method.
- Simulated terahertz radiation from metallic gratings with varying groove depths.
Main Results:
- Observed directional, wide-band THz radiation with sharp peaks emitted from the edge of graded gratings.
- Identified that different spoof SPP modes, originating from distinct locations, contribute to the radiation.
- Demonstrated that radiation direction (forward/backward) and frequency range are controllable by adjusting groove depths.
Conclusions:
- Graded grating structures enable novel THz radiation generation distinct from uniform gratings.
- The findings pave the way for developing advanced THz sources using spoof SPPs in various metallic nanostructures and metasurfaces.
