Plasmonic Design Based Structures For THz Antenna Sources and Detectors

摘要

We review here our efforts to make high power THz sources. We have developed different plasmonic structural designs for the confinement of incident excitation infra-red (800nm, 10fs) laser pulse on SI-GaAs surface. The SI-GaAs surface is modified so that incident radiation is less reflected and more absorbed in the substrate. Fabricating THz antenna structures on it increases the efficiency of the THz source. We have demonstrated this idea in its simplest form by increasing the overall surface area by fabricating trenches on the GaAs surface in the past. The new designs are expected to increase the THz source emission by at least a factor 2 to 4. We have also fabricated quasi-crystal pattern on SI-GaAs substrate to enhance the incident light confinement and checked THz emission from it. The simulated plasmonic structures will be fabricated on the SI-GaAs substrates as well as C-irradiated GaAs substrates. We have shown that our in-house fabricated THz Sources from C-irradiated SI-GaAs showed ~2 orders power increase. The detectors fabricated from these materials showed replica of the incident THz wave compared to the one detected using ZnTe. We will also present use of the C-irradiated substrates in the generation of Continuous Wave (CW) THz sources. All the aforementioned sources have been compared with the commercially available sources made of LT-GaAs.