Significant noise current decrease in a terahertz photoconductive antenna-detector based on a strain-induced InAlAs/InGaAs superlattice

We registered a significant decrease of the noise current of a photoconductive antenna (PCA), which is based on a strain-induced InAlAs/InGaAs superlattice with an ultrashort photocarrier lifetime due to a decrease in the focal spot size of a probe laser beam. We showed that the proposed PCA-detector exhibits merely a 1.5-fold increase of the noise current, while the THz power boost reaches a 10-fold magnitude. This feature can be used, in particular, to detect small THz signals. The PCA-detector shows a $\sim$65 dB in its signal-to-noise ratio within 0.1–4.0 THz bandwidth.