Friday, February 19, 2016
Abstract-Microstructured gradient-index lenses for THz photoconductive antennas
A new type of substrate lens for photoconductive antennas (PCA’s) based on sub-wavelength microstructuring is presented and studied theoretically by the use of methods (GFIEM’s). By etching sub-wavelength trenches into a flat substrate, the effective can be designed to function like a gradient index lens. The proposed substrate have sub-mm dimension, which is smaller than the dimensions of a typical hyper-hemispherical substrate lens (HSL), and could enable of arrays of closely packed PCA’s with individual integrated directly into the PCA substrate. The performance of different is compared to a HSL and shown to be comparable with regards to the extraction efficiency, and it is shown that the collimating properties of these can be tailored by changing the parameters used for microstructuring.