Low-frequency active surface plasmon optics on semiconductors

Abstract

A major challenge in the development of surface plasmon optics or plasmonics is the active control of the propagation of surface plasmon polaritons (SPPs). Here, we demonstrate the feasibility of low-frequency active plasmonics using semiconductors. We show experimentally that the Bragg scattering of terahertz SPPs on a semiconductor grating can be modified by thermal excitation of free carriers. The transmission of SPPs through the grating at certain frequencies can be switched completely by changing the temperature less than 100°C. This semiconductor switch provides a basis for the development of low-frequency surface-plasmon optical devices.

Magneto-optical properties of InSb for terahertz applications

“…The polar Kerr rotation is up to 20 degrees, which is higher than the data on InAs at 0.48 T by Shimano et al, 28 which show Kerr rotation of 10 degrees around 1.5 THz. The strength of this effect at room temperature and reasonably low magnetic field points to applicability of InSb as a material for non-reciprocal magnetoplasmonic devices usable in the terahertz range, plus the properties can easily be further modulated by either heat 29 or light, 23 or the material can be used in a heterostructure in combination with different doping levels. The plasmonic properties can further enhance the magneto-optical effects by capturing, guiding and concentrating light at subwavelength scale using surface plasmons.…”

Two-fluid hydrodynamic model for semiconductors

“…Furthermore, intrinsic semiconductors may contain plasmas created either thermally or by external excitations (e.g., from a laser), and here the electron density can be controlled dynamically with the temperature or the excitation energy, respectively. Plasmonics has already been shown in several papers for doped semiconductors [16][17][18][19][20][21][22][23][24][25][26][27][28], biased semiconductors [29][30][31][32], laser excited semiconductors [33], and thermally excited intrinsic semiconductors [34][35][36][37].…”

Terahertz transmission lines based on surface waves in plasmonic waveguides

“…Low-loss, quasi-TEM, and low-dispersion propagation of terahertz waves has been demonstrated experimentally in both air-filled parallel-plate waveguides 1,2 ͑AF-PPWGs͒ and dielectric-filled parallelplate waveguides 3,4 ͑DF-PPWGs͒. 19,20 While the propagation along MD-SWGs at optical wavelengths is lossy, low-loss propagation of visible and near IR waves is achievable based on the long-range surface plasmon polaritons ͑SPPs͒ in other structures such as symmetrically loaded metal slabs 21,22 and stripes 23 as well as metal-clad waveguides. 13 It is well known that metal-dielectric surface waveguides ͑MD-SWGs͒ also support the propagation of electromagnetic waves in the form of surface plasmon-assisted guided modes, 14,15 ranging from visible and near infrared ͑IR͒ [16][17][18] to far IR and terahertz regions of the spectrum.…”

“…25,26 The low-loss and quasi-TEM nature of terahertz waves propagation in PPWGs and MD-SWGs provokes the idea of employing the transmission line ͑TL͒ theory to study these structures. Nevertheless, aside from its theoretical importance, the metal layer can be replaced by a doped semiconductor 19,20,32 to provide a better confinement. Furthermore, these models are particularly useful for the analysis and design of terahertz traveling-wave devices such as traveling-wave photomixers [27][28][29] and detectors.…”