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21.
Tunable terahertz transmission behaviors and coupling mechanism in hybrid MoS2 metamaterials 下载免费PDF全文
A hybrid metamaterial with the integration of molybdenum disulfide(MoS2)overlayer is proposed to manipulate the terahertz(THz)wave.The simulated results indicate that the introduction of MoS2 layer could significantly modify the resonant responses with large resonance red-shift and bandwidth broadening due to the depolarization field effect,especially for the structure on the small permitivity substrate.Additionally,the wide-band modulator in off-resonant region and a switch effect at resonance can be achieved by varying the conductivity of MoS2 layer.Further theoretical calculations based on the Lorentz coupling model are consistent with the simulated results,explicating the response behaviors originate from the coupling between MoS2 overlayer and the metastructure.Our results could provide a possibility for active control THz modulator and switchable device based on the MoS2 overlayer and advance the understanding of the coupling mechanism in hybrid structures. 相似文献
22.
Transient optical modulation properties in the terahertz metamaterial of split ring resonators 下载免费PDF全文
The ultrafast optical modulation properties of split ring resonators are characterized by utilizing optical pump-terahertz probe spectroscopy.The experimental results show that when the terahertz electric vector is perpendicular to the gap of the split ring resonator,resonant absorption can be quenched significantly under high pump excitation.However,when the terahertz electric vector is parallel to the gap,the resonant absorption is less sensitive to pump excitation due to the structural properties of the metamaterial.Our numerical simulations also demonstrate that the pump pulse significantly influences the split ring resonator current by generating carriers in the substrate. 相似文献
23.
The spatiotemporal and spectral characteristics of
ultrawide-band terahertz pulses after passing through a Fresnel lens
are studied by using the scalar diffraction theory. The simulation
shows that the transmitted terahertz waveforms compress with
increasing propagation distance, and the multi-frequency focusing
phenomenon at different focal points is observed. Additionally, the
distribution of terahertz fields in a plane perpendicular to the
axis is also discussed, and it is found that the diffraction not
only induces focusing on-axis but also inhibits focusing at off-axis
positions. Therefore, the Fresnel lens may be a useful alternative
approach to being a terahertz filter. Moreover, the terahertz pulses
travelling as a basic mode of a Gaussian beam are discussed in
detail. 相似文献