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Design, Fabrication, and Experimental Characterization of Plasmonic Photoconductive Terahertz Emitters
Published on: July 8, 2013
High-contrast terahertz modulator based on extraordinary transmission through a ring aperture
Jie Shu1, Ciyuan Qiu, Victoria Astley
1Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005, USA.
Optics Express
|January 26, 2012
Summary
We achieved high terahertz transmission using ring apertures in metal films. This THz transmission can be modulated by controlling free carriers, paving the way for CMOS-compatible terahertz modulators.
Area of Science:
- Optics and Photonics
- Materials Science
- Electrical Engineering
Background:
- Terahertz (THz) transmission through subwavelength apertures is crucial for THz technologies.
- Achieving high transmission efficiency with small apertures remains a challenge.
- Modulating THz waves efficiently is key for applications like imaging and communication.
Purpose of the Study:
- To demonstrate and characterize extraordinary THz transmission through specifically designed ring apertures.
- To investigate the modulation capabilities of this THz transmission system.
- To explore the potential for developing CMOS-compatible THz modulators.
Main Methods:
- Fabrication of a metal film with precisely patterned ring apertures.
- Measurement of THz transmission spectra through the apertures.
- Integration of a silicon substrate with controllable free carrier density beneath the apertures.
- Characterization of transmission modulation by varying carrier density.
Main Results:
- Extraordinary THz transmission exceeding 60% was achieved with a low aperture-to-area ratio (1.4%).
- High THz transmission was suppressed by over 18 dB upon introducing a thin layer of free carriers in the silicon substrate.
- The transmission modulation is directly linked to the carrier density near the apertures.
Conclusions:
- Ring apertures enable highly efficient THz transmission.
- Free carrier modulation offers an effective method to control THz transmission through these apertures.
- This research suggests a viable pathway for creating CMOS-compatible terahertz modulators.
