Article

Nanoconcentration of Terahertz Radiation in Plasmonic Waveguides

Department of Physics and Astronomy, Georgia State University, Atlanta, Georgia 30303, USA.
Optics Express (Impact Factor: 3.49). 12/2008; 16(23):18576-89. DOI: 10.1364/OE.16.018576
Source: PubMed

ABSTRACT We establish the principal limits for the nanoconcentration of the THz radiation in metal/dielectric waveguides and determine their optimum shapes required for this nanoconcentration. We predict that the adiabatic compression of THz radiation from the initial spot size of R(0) approximately lambda(0) to the final size of R = 100- 250 nm can be achieved, while the THz radiation intensity is increased by a factor of x10 to x250. This THz energy nanoconcentration will not only improve the spatial resolution and increase the signal/noise ratio for the THz imaging and spectroscopy, but in combination with the recently developed sources of powerful THz pulses will allow the observation of nonlinear THz effects and a variety of nonlinear spectroscopies (such as two-dimensional spectroscopy), which are highly informative. This will find a wide spectrum of applications in science, engineering, biomedical research, environmental monitoring, and defense.

Download full-text

Full-text

Available from: Maxim Durach, Aug 19, 2015
0 Followers
 · 
173 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this Letter we develop a theory of spoof plasmons propagating on real metals perforated with planar periodic grooves. Deviation from the spoof plasmons on perfect conductor due to finite skin depth has been analytically described. This allowed us to investigate important propagation characteristics of spoof plasmons such as quality factor and propagation length as the function of the geometrical parameters of the structure. We have also considered THz field confinement by adiabatic increase of the depth of the grooves. It is shown that the finite skin depth limits the propagation length of spoof plasmons as well as a possibility to localize THz field. Geometrical parameters of the structure are found which provide optimal guiding and localization of THz energy.
    Applied Physics A 06/2010; 100(2):375-378. DOI:10.1007/s00339-010-5866-y · 1.69 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This research reports an experimental and simulation study of a silicon-lens-free tapered parallel-plate waveguide (TPPWG) to improve THz coupling to the plate separation gap. The TPPWG without any silicon lens is compared to the parallel-plate waveguide (PPWG) with a plano-cylindrical silicon lens. It was found that the input- and output-side TPPWG with a 3° tapered slop angle increased by about 103% at 1 THz compared to the PPWG.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We introduce an approach to implement full coherent control on nanometer length scales. It is based on spatiotemporal modulation of the surface plasmon polariton (SPP) fields at the thick edge of a nanowedge. The SPP wavepackets propagating toward the sharp edge of this nanowedge are compressed and adiabatically concentrated at a nanofocus, forming an ultrashort pulse of local fields. The profile of the focused waveform as a function of time and one spatial dimension is completely coherently controlled. We establish the principal limits for the nanoconcentration of the terahertz (THz) radiation in metal/dielectric waveguides and determine their optimum shapes required for this nanoconcentration. We predict that the adiabatic compression of THz radiation from the initial spot size of vacuum wavelength R0 ≈ lambda0 ≈ 300 microm to the unprecedented final size of R = 100--250 nm can be achieved, while the THz radiation intensity is increased by a factor of 10 to 250. This THz energy nanoconcentration will not only improve the spatial resolution and increase the signal/noise ratio for THz imaging and spectroscopy, but in combination with the recently developed sources of powerful THz pulses, will allow the observation of nonlinear THz effects and a variety of nonlinear spectroscopies (such as two-dimensional spectroscopy), which are highly informative. This should find a wide spectrum of applications in science, engineering, biomedical research and environmental monitoring. We also develop a theory of the spoof plasmons propagating at the interface between a dielectric and a real conductor. The deviation from a perfect conductor is introduced through a finite skin depth. The possibilities of guiding and focusing of spoof plasmons are considered. Geometrical parameters of the structure are found which provide a good guiding of such modes. Moreover, the limit on the concentration by means of planar spoof plasmons in case of non-ideal metal is established. These properties of spoof plasmons are of great interest for THz technology. INDEX WORDS: Nanoplasmonics, Surface plasmon polaritons, Adiabatic concentration, Full coherent control on nanoscale, Nanowedge, Terahertz, Coaxial waveguide, Spoof plasmons, Nanoscale, Nanofocus, Terahertz (THz) energy nanoconcentration
Show more