The Theoretical Research Of The Surface Plasma Polaritons At Th_z Frequency

Surface plasmon polaritons (SPP_s) is a kind of mixed excited states,formed by the mutual coupling of the surface plasmons and the incidentphotons, bounding to the surface and propagating along the metal anddielectric interface. SPP_s have been researched intensively for itspotential application value in electronics and photonics. Most of the workare focused on metallic SPP_s at optical frequency,but little in TH_z range.TH_z has been regarded as one of the most important science andtechnology issues in this century. Besides owning huge potentialapplication value in scientific research,TH_z technology also provides anefficient and powerful method for other research domains. The purpose ofthis paper is the theoretical research of SPP_s at TH_z frequency. The workand achievements are as follows:1. Starting from the Maxwell equations, the dispersion relation ofSPP_s is derived, and several characteristic parameters of SPP_s areintroduced. And the reason for SPP_s' excitation can only by TM mode isalso discussed. The plasma frequency and complex dielectric constant arededuced from the Drude model, both of the two causing main influence to SPP_s.2. The characteristic parameters of SPP_s of gold and indiumantimonide semiconductor at one TH_z radiation have been calculated.A conclusion is derived from the comparison of all the characteristicparameters of SPP_s: metals are no longer suitable for the excitation ofSPP_s at TH_z frequency, for the weak coupling between electrons andTH_z, while the semiconductors are doing well. The metallic dielectricconstant is quite large at TH_z frequency, which causing serious surfaceimpedance imbalances.3. The characteristic parameters of InAs, InP, GaAs semiconductorSPP_s have been calculated too. Finding that: the carrier concentration ofsemiconductor can be easily tuned through doping, achieving the activecontrol of SPP_s.4. The plasma frequency and dielectric constant of superconductorhave been calculated through the two-fluid-model. Superconductor is alsosuitable for the excitation of SPP_s at TH_z frequencies.