FREQUENCY-DEPENDENT PROPERTIES OF InGaAs BOW-TIE DETECTORS IN TERAHERTZ RANGE

Finite-difference time-domain simulation results in bow-tie InGaAs diodes are presented. Dependences of electric field amplitude on frequency were investigated for various device shapes and sizes. It was shown that two metallized parts of the bow-tie type detector act as the separate antennas causing thus the experimentally observed fast sensitivity reduction at 1.63, 1.83, and 2.51 THz frequencies. Moreover, it has been demonstrated that the estimated effective average refractive index of the region around the antenna for all investigated angles and dimensions is nearly constant, and this constant value could be used for further estimation of frequency dependent properties in the case of other slightly altered bow-tie detector geometry.