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Published on: July 24, 2015
Low threshold optical bistability at terahertz frequencies with graphene surface plasmons
Xiaoyu Dai1, Leyong Jiang1, Yuanjiang Xiang1
1SZU-NUS Collaborative Innovation Center for Optoelectronic Science &Technology, Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China.
We present a novel terahertz optical bistable device using graphene-integrated dielectric structures. This configuration significantly lowers switching thresholds for optical bistability, enabling tunable terahertz devices.
Area of Science:
- Terahertz (THz) photonics
- Plasmonics
- Materials science
Background:
- Optical bistability is crucial for all-optical signal processing.
- Conventional Kretschmann-Raether configurations often require high optical intensities.
- Terahertz frequencies present unique challenges and opportunities for optical devices.
Purpose of the Study:
- To propose and investigate a modified Kretschmann-Raether configuration for low-threshold optical bistable devices at terahertz frequencies.
- To explore the role of graphene in enhancing surface electromagnetic wave excitation.
- To identify parameters for tuning the optical bistability characteristics.
Main Methods:
- Modification of the Kretschmann-Raether configuration by replacing the metal layer with a graphene-embedded dielectric sandwich structure.
- Theoretical analysis of TM-polarized surface electromagnetic wave propagation and excitation.
- Investigation of the dependence of surface plasmon resonance on graphene's Fermi-level and dielectric layer thickness.
Main Results:
- The modified configuration supports TM-polarized surface electromagnetic waves.
- Excitation of graphene surface plasmons significantly lowers the switching-up and switching-down intensities for optical bistability.
- The switching threshold can be further reduced by decreasing the Fermi-level or increasing the dielectric sandwich thickness.
Conclusions:
- The proposed graphene-based dielectric structure offers a promising pathway for realizing low-threshold, tunable optical bistable devices in the terahertz range.
- This approach provides a new method for controlling and optimizing optical bistability at terahertz frequencies.
- Further investigation into higher terahertz frequencies and the impact of relaxation time is warranted for practical applications.
