Enhanced THz radiation emission from plasmonic complementary Sierpinski fractal emitters

Abstract

We present a new class of plasmonic photoconductive THz emitters based on a complementary Sierpinski gasket fractal geometry. Due to the presence of sub-wavelength perforations on the surface of the antenna, these antennae operate in the plasmonic regime. By utilizing the unique self-similar and space filling of the tailored fractal surface and the plasmonic surface current spatial distribution, photoconductive THz emitters exhibiting superior performance (~80% increase in the emitted THz radiation power) to conventional bow-tie and Sierpinski gasket THz emitters are demonstrated. It is shown that the self-similarity of the surface plasmon current present on the antenna surface is responsible for this emission enhancement.

Effects of Antenna Design Parameters on the Characteristics of a Terahertz Coplanar Stripline Dipole Antenna

“…Various antenna designs, such as bow-tie [12], logarithm spiral [13], strip line [14], strip line dipole [15,16], and fractal-based antennas [17,18], have received significant attention for better generation and detection of THz radiation [19]. One of the most popular designs is the one that involves the use of a stripline dipole antenna, in which a center dipole is connected to coplanar striplines and forms an H-shaped electrode structure.…”

Validation of electromagnetic field enhancement in near-infrared through Sierpinski fractal nanoantennas

“…Another theoretical study pointed out that by designing plasmonic Sierpiński fractal bowtie antennas, it is possible to enhance the electric field within the gap, tune the spectral response at the near-infrared (NIR) wavelength regime, and redshift the resonance wavelength after each iteration [22]. The influence of the Hausdorff dimension (D s ) on the tunability of the Sierpiński nanoantenna was studied in another work [23], whereas a photoconductive THz emitter was proposed by utilizing complementary Sierpiński fractal geometries [24]. Rosa et al considered a Sierpiński fractal plasmonic nanoantenna in [25], which would work by enhancing the extinction cross section in multiple bands.…”

Experimental Confirmation of Design Techniques for Effective Bow-Tie Antenna Lengths at THz Frequencies

“…For efficient coupling of the generated THz radiation from substrate into free space, integrated antennas were introduced to the PC switches. To date, significant attention has been given to utilizing various antenna designs, such as bow-tie [3], strip line [4,5], strip line dipole [6,7] as well as fractal based [8,9] antennae for better generation and detection of THz radiation. Consequently, there have been investigations of the relationship between the geometric design parameters of strip line dipole antennas and their emitted THz radiation properties [4,7,10].…”