This Letter proposes a novel method for enhancing terahertz (THz) radiation from microstructure photoconductive antennas (MSPCA). We present two types of MSPCA, which contain split-ring resonators (SRRs) and dipole photoconductive antennas (D-PCAs). The experimental results reveal that when the femtosecond laser is pumping onto the split position of the SRR, the maximum THz radiation power is enhanced by 92 times compared to pumping at the electrode edge of the D-PCA. Two π phase shifts occur as the pumping laser propagates from the negative electrode to the positive electrode. Analysis shows that photoinduced carrier charges move within the split position of the SRR.
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