Fractal Structures for THz Radiation Emitters

We present a review on a special class of photoconductive (PC) terahertz (THz) dipole emitters based on fractal geometry. A comprehensive study of these superior THz antenna designs that are able to emit higher THz radiation power and detect lower THz radiation signal levels than the traditional THz PC antennas is performed. It is shown that the presented fractal PC THz emitters operate in a plasmonic regime. This concept is applicable to all fractal geometries such as Sierpinski and Apollonian fractals. In addition, the effect of self-similar geometry on radiation properties of fractal PC THz emitters is presented.