Resonant plasmonic excitations in micro-scale structures at terahertz (THz) frequencies can make a large impact development of THz devises. A number of material systems have been proposed and demonstrated for THz plasmonic resonators, including doped semiconductors, materials with metallic behavior, such as graphene, graphite, and carbon nano-tubes, superconductors and topological insulators. However, experimental investigations of THz plasmonic resonators, which are typically a fraction of the free space wavelength in size, remain challenging. We demonstrate that THz near-field spectroscopy and imaging technique based on a subwavelength aperture probe can be employed to detect excitation of THz plasmons in carbon micro-fibers. Upon excitation of a single carbon fiber by a THz pulse, we observe a standing wave formed along the fiber length. The resonant frequency is consistent with the fundamental dipole mode, both in its value and in its dependence on the fiber length. The field of the standing wave is localized and it indicates the plasmonic nature of the excitation. The fact that the resonance frequency also depends on the material conductivity allows us to employ the THz near-field spectroscopy method to evaluate the material conductivity non-invasively. Furthermore we propose an alternative method for non-contact conductivity probing. It utilizes the relative amplitude of the surface plasmon field that can be measured by the near-field probe. The amplitude increases with the fiber conductivity and therefore it can be used for conductivity estimation.
This paper presents the development of heterodyne receiver configurations based on EBG technology. The basic required
building blocks, waveguides and cavities are first described. A subhamonic EBG receiver design is finally presented.
This work presents a fully vector plane wave method suitable for eigenwaves characteristics calculation for periodic
dielectric media with arbitrary geometry and dimension, consisting of either isotropic or anisotropic materials. Using the
method concerned, the influence of anisotropic material molecules reorientation in a photonic crystal on the symmetry
properties of the dispersion surface of the latter. The work explains how the 2D anisotropic photonic crystal Brillouin
zone shape depend on the anisotropic molecules orientation.
Present paper is devoted to studying the properties of anisotropic photonic crystal media and developing algorithms for
calculating them. Plane wave method suitable for three-dimensional anisotropic periodic media was used to obtain the
matrix equation yielding the eigenwaves characteristics of the structures concerned. As a particular case, properties of
two-dimensional photonic crystals filled with liquid crystal elements were analyzed. Different variants of dispersion
properties tuning were discussed.
The results of numerical modeling and experimental investigations of manufactured diamond-shaped and large area hollow core photonic crystal fibers with periodical cladding (kagome-lattice and closely packed tubes) are presented. The use of soft glasses allows to fabricate high-quality structures with moderate losses. Numerical methods, designing strategies and fabrication issues of these promising fiber structures are discussed.
In the present paper photonic crystal fiber properties were studied. Group velocity dispersion and nonlinearity factor of the fiber were obtained. Pulse parameters, needed for fundamental-mode or high-index-mode solitons to form such fibers, were estimated.
This work is devoted to studying the phenomenon of refraction at an interface of a two-dimensional photonic crystal (PC) and a uniform dielectric. Refraction laws were obtained by means of isofrequency method. Different types of refraction depending on the incident wave vector, outer medium and PC refraction indexes and mutual orientation of the interface and PC symmetry axis were observed.