Efficient three-dimensional photonic–plasmonic photoconductive switches for picosecond THz pulses

Georgiou, G. , Geffroy, C., Clément, C. and Roux, J.-F. (2020) Efficient three-dimensional photonic–plasmonic photoconductive switches for picosecond THz pulses. ACS Photonics, 7(6), pp. 1444-1451. (doi: 10.1021/acsphotonics.0c00044)

Abstract

The efficiency of photoconductive switches, which continue to be used for the generation and detection of THz waves, has been overlooked for a long time. The so far “optics-dominated” devices are making their way through to new and emerging fields of research that require ultrafast picosecond voltage pulses, as well as to new applications where power efficiency is of uttermost importance. To address the efficiency problems, in this Article we present a novel photoconductive switch that is based on a three-dimensional design. In contrast to conventional planar designs, our photoconductive switch drastically enhances the overall efficiency by maximizing the laser absorption within the device, while at the same time optimizing the carrier collection efficiency at the electrodes. To maximize the optical absorption, we take advantage of photonic and plasmonic modes that are excited in our device due to a periodic array of nanopillars, whereas the collection efficiency is optimized by converting each nanopillar into a single nano-photoconductive switch. Our numerical calculations show a 50-fold increase in the overall generated current and a 5-fold bandwidth increase compared to traditional interdigitated planar photoconductive switches. This opens up a wealth of new possibilities in quantum science and technology where efficient low power devices are indispensable.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Georgiou, Dr Giorgos
• Authors: Georgiou, G., Geffroy, C., Clément, C., and Roux, J.-F.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: ACS Photonics
• Publisher: American Chemical Society
• ISSN: 2330-4022
• ISSN (Online): 2330-4022
• Published Online: 28 May 2020