Abstract-Terahertz radiation enhancement in dipole photoconductive antenna on LT-GaAs using a gold plasmonic nanodisk array

Mohammad Bashirpour, Jafar Poursafar. Mohammadreza Kolahdouz,  Mohsen Hajari, Matin Forouzmehr, Mohammad Neshat. Hamid Hajihoseini, Morteza Fathipour, Zahra Kolahdouz, Guoqi Zhang,



https://www.sciencedirect.com/science/article/pii/S0030399219308904

This study proposes a new-fashioned plasmonic photoconductive antenna (PCA) with high optical-to-terahertz (THz) conversion efficiency. Finite element method was used to investigate and optimize the interaction of 800 nm femtosecond laser with the designed nanodisk array in the antenna’s gap using its geometrical parameters. According to the simulation results, our optimized nanoplasmonic structure showed more than 38% enhancement in the absorption efficiency compared to the conventional structure without any nanostructure. Measuring the THz radiation of the fabricated PCAs using a time domain spectroscopy setup exhibited an exceptional 5.6 times higher electric field in 0.1–2.5 THz range compared to a similar PCA but without nanoplasmonic structure.

Abstract-Thin Film Tandem Nanoplasmonic Photoconductive Antenna for High Performance Terahertz Detection

Saman Ghorbani, 

Mohammad Bashirpour, 

Jafar Poursafar, 

Mohammadreza Kolahdouz, 

Mohammad Neshat, 

Amirali Valinejad

https://www.sciencedirect.com/science/article/pii/S0749603618309352
Photoconductive antennas (PCA) have attracted lots of attention for terahertz application, due to their room temperature operation and compact design. On the other hand, their main problem is acquiring low output power. Lately, plasmonic structures of different geometries have been proposed to overcome the mentioned issue. Here, we have proposed and simulated a PCA on a silicon-on-sapphire substrate and a layout of a plasmonic nanostructure in which the effect of geometrical parameters of the nanostructure on PCA’s output was investigated and optimized. According to the results for one layer plasmonic nanostructure, two different geometries showed more than 700% improvement in the device photocurrent which are related to different types of surface plasmons. By combining these layouts and benefiting from both simultaneously, a final proposed nanostructure was constructed. After optimizing the new structure’s parameters, a significant increase of 15400% in photocurrent enhancement was achieved by comparing to the conventional THz PCAs on similar substrate.