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采用磁控溅射法制备了金属Cr膜,并利用太赫兹时域光谱法获得了其光学参数.利用Cr膜的光学参数计算了其相位穿透深度,设计了基于低温GaAs的全金属平面微腔光电导太赫兹辐射器件.模拟结果表明:器件的谐振频率分别为0.32,0.65,0.98,1.31和1.65 THz,与自由空间的光电导太赫兹谱相比,在谐振频率为0.32 THz处的峰值强度提高了25倍,光谱半高全宽压缩了50倍.讨论了辐射偶极子与腔内驻波场之间的耦合强度对器件辐射强度的影响,发现当辐射中心位于驻波场波腹处时,器件辐射最强,位于波节处时辐射被严重抑制.太赫兹波段微腔效应的研究对于实现单色性好,连续调谐,高效高辐射强度的太赫兹源具有一定的理论意义.
Cr films were prepared by magnetron sputtering and their optical parameters were obtained by terahertz time-domain spectroscopy.The phase penetration depth was calculated by the optical parameters of the Cr film. All-metal planar micro-structures based on low-temperature GaAs Cavity photoconductive terahertz radiation device.The simulation results show that the resonant frequencies of the devices are 0.32, 0.65, 0.98, 1.31 and 1.65 THz, respectively, compared with the photoconductive terahertz spectrum in free space, the peak at the resonant frequency of 0.32 THz The intensity is increased by 25 times and the full width at half maximum of the spectrum is compressed by 50 times.The influence of the coupling strength between the radiation dipole and the standing wave field in the cavity on the radiation intensity of the device is discussed and it is found that when the radiation center is located at the antinode of the standing wave field , The radiation of the device is the strongest and the radiation is severely restrained when located at the node.The study of terahertz waveband microcavity has certain theoretical significance for realizing terahertz source with good monochromaticity, continuous tuning and high efficiency and high radiation intensity.