Scalable Large-Area Terahertz Emitters with Improved Electrode Design

We have systematically investigated the influence of electrode parameters on the emission efficiency of scalable large area photoconductive THz emitters. We identify two contributions to THz emission, originating from the photoexcited carriers in the semiconductor and from the interdigitated metal electrodes acting as dipole antennae, respectively. Both contributions are optimized for maximum THz emission efficiency by varying the gap and stripe widths of the interdigitated metal electrodes. Using this approach we achieve a 50% improvement of the radiated THz electric field as compared to electrodes with equal stripe and gap widths.