The influence of air gaps on the response of transmission for a transverse-electric mode parallel-plate waveguide(TE-PPWG)with a single cavity and double cavities has been studied experimentally.As the air gap is larg...The influence of air gaps on the response of transmission for a transverse-electric mode parallel-plate waveguide(TE-PPWG)with a single cavity and double cavities has been studied experimentally.As the air gap is larger than the resonant wavelength of high order cavity mode in the single deep grooved waveguide,only the fundamental cavity mode can be excited and single resonance can be observed in the transmission spectrum.Based on above observations,a tunable multiband terahertz(THz)notch filter has been proposed and the variation of air gap has turned out to be an effective method to select the band number.Experimental data and simulated results verify this band number tunability.This mechanical control mechanism for electromagnetic induced transparency(EIT)will open a door to design the tunable THz devices.展开更多
A proof is offered for the equivalence of the energy velocity and the group velocity in the case where the group velocity may be negative while the wavenumber is positive. The explicit expression for both the energy ...A proof is offered for the equivalence of the energy velocity and the group velocity in the case where the group velocity may be negative while the wavenumber is positive. The explicit expression for both the energy velocity and the group velocity is obtained for waves in an isotropic homogeneous plate waveguide. Calculations show the values of the group velocity or the energy velocity to be negative for some frequencies.展开更多
基金supported by the National Program on Key Basic Research Project of China under Grant No.2014CB339806Basic Research Key Project under Grant No.12JC1407100+1 种基金Major National Development Project of Scientific Instrument and Equipment under Grant No.2011YQ150021 and No.2012YQ14000504the National Natural Science Foundation of China under Grant No.11174207,No.61138001,No.61205094,and No.61307126
文摘The influence of air gaps on the response of transmission for a transverse-electric mode parallel-plate waveguide(TE-PPWG)with a single cavity and double cavities has been studied experimentally.As the air gap is larger than the resonant wavelength of high order cavity mode in the single deep grooved waveguide,only the fundamental cavity mode can be excited and single resonance can be observed in the transmission spectrum.Based on above observations,a tunable multiband terahertz(THz)notch filter has been proposed and the variation of air gap has turned out to be an effective method to select the band number.Experimental data and simulated results verify this band number tunability.This mechanical control mechanism for electromagnetic induced transparency(EIT)will open a door to design the tunable THz devices.
文摘A proof is offered for the equivalence of the energy velocity and the group velocity in the case where the group velocity may be negative while the wavenumber is positive. The explicit expression for both the energy velocity and the group velocity is obtained for waves in an isotropic homogeneous plate waveguide. Calculations show the values of the group velocity or the energy velocity to be negative for some frequencies.
