Performance characterization of a self-made terahertz photoconductive antenna

A terahertz (THz) photoconductive antenna is prepared using, to the best of our knowledge, a novel method, which has high yield and strong stability. It eliminates the stripping process of a thin-film THz antenna and effectively prevents the toxicity of the corrosion solution, the easy damage in the transfer process, and the weak bonding with the substrate. First, a 200 µm copper wire is bundled on a low-temperature GaAs epitaxial wafer, and then the electrode of the photoconductive antenna is fabricated using the vacuum evaporation method. Finally, the THz time-domain signal with a high signal-to-noise ratio and good repeatability is obtained using an 800 nm laser. Additionally, the influence of pump light and detection light power on THz signal intensity is studied when the total optical power is unchanged. Results show that when the total power of the laser is greater than a certain value, there is an optimal ratio between the pump power and the detection power, which can maximize the signal-to-noise ratio of the THz wave. This provides a basis for the effective application of a THz antenna and lays a foundation for improving the detection sensitivity of samples.