Emission Properties of YBa2Cu3O7-δ-Film Photoswitches as Terahertz Radiation Sources
Emission Properties of YBa2Cu3O7-δ-Film Photoswitches as Terahertz Radiation Sources
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YBa2Cu3O7-δ-薄膜光电开关作为太赫兹辐射源的发射特性
DOI：
10.1143/jjap.36.1984
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发表时间：
1997
影响因子：
1.5
通讯作者：
Kiyomi Sakai Kiyomi Sakai
中科院分区：
文献类型：
--
作者：
M. Tani;M. Tonouchi;M. Hangyo;Zhen Wang;Noriaki Onodera Noriaki Onodera;Kiyomi Sakai Kiyomi Sakai
利用飞秒激光脉冲激励偏置的YBa 2Cu 3 O 7-δ（YBCO）薄膜光开关产生太赫兹（THz）辐射。测量了泵浦功率、偏置电流和辐射幅度随温度的变化关系，以表征高临界温度超导光开关的辐射特性。在中等抽运功率范围内，辐射幅度随抽运功率的增加呈超线性增加，在高抽运功率时达到饱和。偏置电流的辐射振幅的依赖性表现出超线性增加的高偏置电流。除临界温度附近外，辐射振幅的温度依赖性随着温度的升高而增大。测量中观察到的特征被解释为热的和瞬态的复折射率的变化，这影响了太赫兹辐射的输出耦合效率从高温C超导薄膜的自由空间。
Terahertz (THz) radiation is generated from biased YBa2Cu3O7-δ (YBCO)-film photoswitches by exciting them with femtosecond (fsec) laser pulses. The pump power, bias current and temperature dependence of the radiation amplitude is measured in order to characterize the emission properties of the high-critical-temperature (high-T C) superconducting photoswitches. The radiation amplitude increases superlinearly with increasing pump power in the moderate pump power range and saturates at high pump power. The bias current dependence of the radiation amplitude shows superlinear increase for high bias current. The temperature dependence of the radiation amplitude increases with increasing temperature except near the critical temperature. The features observed in the measurements are explained by the thermal and transient changes of the complex refractive index, which affects the output coupling efficiency of the THz radiation from the high-T C superconducting film to the free space.