Design and performance enhancement of terahertz photoconductive antenna based on nano-crossline contacts

• Published in: Optik (Stuttgart) 2023-09, Vol.287, p.171057, Article 171057
• Main Authors: Falih, Ahmed S., Hubeatir, Kadhim A., Fyath, Raad S.
• Format: Article
• Language: English
• Subjects: Buried Nano-crossline (BN-CL); Nano-crossline (N-CL) contacts; Photoconductive antenna (PCA); Terahertz
• ISSN: 0030-4026; 1618-1336
• DOI: 10.1016/j.ijleo.2023.171057

Photoconductive antennas (PCAs) of high conversion efficiency is an essential device for generating or detecting terahertz (THz) waves. This paper presents an enhanced THz-PCA by incorporating buried nano-crosslines (BN-CL) contacts to offer high optical-to-terahertz power conversion efficiency. The BN-CL contact makes that most photocarriers are created at nanoscale distances from the PCA electrodes and, hence, carries drift in a sub-picosecond duration to generate THz radiation. The full-wave multiphysics model is used for the hybrid simulation of THz PCAs and investigated the impact of geometrical variables on a proposed PCA's transient photocurrent. The designed THz antenna has a bandwidth of more than 4 THz and high efficiency of 94%. Both designs of BN-CL and N-CL are implemented with and without double dielectric layers of anti-reflection coating (ARC) and distributed Bragg reflector (DBR) layers. The obtained results of the transient photocurrent are 891 μA and 1089 μA for 10 elements of implemented BN-CL and N-CL contacts, respectively. The photocurrent of BN-CL contacts is enhanced to 1464 μA when 50 element contacts are used. Also, the conversion efficiency of this PCA reaches a maximum value of 1.032% at a pump power of 1.5 mW.