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Low threshold optical bistability at terahertz frequencies with graphene surface plasmons.

Dai X, Jiang L, Xiang Y - Sci Rep (2015)

Bottom Line: It is found that the switching-up and switching-down intensities required to observe the optical bistable behavior are lowered markedly due to the excitation of the graphene surface plasmons, thus making this configuration a prime candidate for experimental investigation at the terahertz range.And the switching threshold value can be further reduced by decreasing the Fermi-level or increasing the thickness of sandwich structure, hence providing a new way for realizing tunable optical bistable devices.Finally, the optical bistability at higher terahertz frequency and the influence of relaxation time under the actual experimental condition on Fermi-level are discussed.

View Article: PubMed Central - PubMed

Affiliation: SZU-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.

ABSTRACT
We propose a modified Kretschmann-Raether configuration to realize the low threshold optical bistable devices at the terahertz frequencies. The metal layer is replaced by the dielectric sandwich structure with the insertion of graphene, and this configuration can support TM-polarization surface electromagnetic wave. The surface plasmon resonance is strongly dependent on the Fermi-level of graphene and the thickness of the sandwich structure. It is found that the switching-up and switching-down intensities required to observe the optical bistable behavior are lowered markedly due to the excitation of the graphene surface plasmons, thus making this configuration a prime candidate for experimental investigation at the terahertz range. And the switching threshold value can be further reduced by decreasing the Fermi-level or increasing the thickness of sandwich structure, hence providing a new way for realizing tunable optical bistable devices. Finally, the optical bistability at higher terahertz frequency and the influence of relaxation time under the actual experimental condition on Fermi-level are discussed.

No MeSH data available.


Related in: MedlinePlus

(a) Dependence of reflectance on the incident angle at the different Fermi-level of graphene; (b) Dependence of transmitted electric field on the incident electric field for EF = 0.6 eV, 0.8 eV and 1.0 eV, respectively, where λ = 100 um, np = ns = 4, n1 = n2 = 1.5, d = 10 um.
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f6: (a) Dependence of reflectance on the incident angle at the different Fermi-level of graphene; (b) Dependence of transmitted electric field on the incident electric field for EF = 0.6 eV, 0.8 eV and 1.0 eV, respectively, where λ = 100 um, np = ns = 4, n1 = n2 = 1.5, d = 10 um.

Mentions: We have investigated the angular dependence of the reflectivity for f = 3THz, as shown in Fig. 6(a). It is obviously that EF = 0.53 eV is large enough to excite SPPs, and the angular positions of the reflectance minima shifts to a smaller angle with the increase of the Fermi-level. Figure 6(b) displays the curves of the optical bistability at the different Fermi-level and incident angle. These curves are further evidence of the possibility to realize the optical bistability at higher THz frequencies with low Fermi-level.


Low threshold optical bistability at terahertz frequencies with graphene surface plasmons.

Dai X, Jiang L, Xiang Y - Sci Rep (2015)

(a) Dependence of reflectance on the incident angle at the different Fermi-level of graphene; (b) Dependence of transmitted electric field on the incident electric field for EF = 0.6 eV, 0.8 eV and 1.0 eV, respectively, where λ = 100 um, np = ns = 4, n1 = n2 = 1.5, d = 10 um.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4508658&req=5

f6: (a) Dependence of reflectance on the incident angle at the different Fermi-level of graphene; (b) Dependence of transmitted electric field on the incident electric field for EF = 0.6 eV, 0.8 eV and 1.0 eV, respectively, where λ = 100 um, np = ns = 4, n1 = n2 = 1.5, d = 10 um.
Mentions: We have investigated the angular dependence of the reflectivity for f = 3THz, as shown in Fig. 6(a). It is obviously that EF = 0.53 eV is large enough to excite SPPs, and the angular positions of the reflectance minima shifts to a smaller angle with the increase of the Fermi-level. Figure 6(b) displays the curves of the optical bistability at the different Fermi-level and incident angle. These curves are further evidence of the possibility to realize the optical bistability at higher THz frequencies with low Fermi-level.

Bottom Line: It is found that the switching-up and switching-down intensities required to observe the optical bistable behavior are lowered markedly due to the excitation of the graphene surface plasmons, thus making this configuration a prime candidate for experimental investigation at the terahertz range.And the switching threshold value can be further reduced by decreasing the Fermi-level or increasing the thickness of sandwich structure, hence providing a new way for realizing tunable optical bistable devices.Finally, the optical bistability at higher terahertz frequency and the influence of relaxation time under the actual experimental condition on Fermi-level are discussed.

View Article: PubMed Central - PubMed

Affiliation: SZU-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.

ABSTRACT
We propose a modified Kretschmann-Raether configuration to realize the low threshold optical bistable devices at the terahertz frequencies. The metal layer is replaced by the dielectric sandwich structure with the insertion of graphene, and this configuration can support TM-polarization surface electromagnetic wave. The surface plasmon resonance is strongly dependent on the Fermi-level of graphene and the thickness of the sandwich structure. It is found that the switching-up and switching-down intensities required to observe the optical bistable behavior are lowered markedly due to the excitation of the graphene surface plasmons, thus making this configuration a prime candidate for experimental investigation at the terahertz range. And the switching threshold value can be further reduced by decreasing the Fermi-level or increasing the thickness of sandwich structure, hence providing a new way for realizing tunable optical bistable devices. Finally, the optical bistability at higher terahertz frequency and the influence of relaxation time under the actual experimental condition on Fermi-level are discussed.

No MeSH data available.


Related in: MedlinePlus