Optimization of wide band mesa-type enhanced terahertz photoconductive antenna at 1550 nm

Xu Jian-Xing^{1, 2}, Li Jin-Lun¹, Wei Si-Hang^{1, 2}, Ma Ben^{1, 2}, Zhang Yi³, Zhang Yu^{1, 2}, Ni Hai-Qiao^{1, 2, †}, Niu Zhi-Chuan^{1, 2}

(color online) Amplitudes versus (a) time delay and (b) frequency for the devices with different gap sizes.