[19a-P3-1~14] 3.9 Terahertz technologies

[19a-P3-9] Comparison of Si lens and tapered transmission line as photoconductive antenna-free space coupler

〇Osamu Morikawa¹, Takuya Yasutsune¹, Kohji Yamamoto², Kazuyoshi Kurihara², Fumiyoshi Kuwashima³, Masahiko Tani² (1.JCGA, 2.Univ. Fukui, 3.FUT)

Keywords:transmission line, superfocusing, THz wave

Si lenses are frequently employed for a photoconductive antenna-free space coupler. Recently, tapered transmission lines have been proposed for that purpose. In this presentation, we compared the Si lens and tapered transmission line as the coupler. Focusing of laser beam to the photoconductive gap of the antenna was changed when the Si lens was replaced to the tapered transmission line. Therefore we measured the current induced in the photoconductive antenna when voltage was applied to the antenna and compensate the effect of the change of focusing using the current value. We found that the signal is stronger and the spectral range is wider when we use the Si lens than the tapered transmission line.