Measurement of nonlinear absorption coefficients in GaAs, InP and Si by an optical pump THz probe technique
Measurement of nonlinear absorption coefficients in GaAs, InP and Si by an optical pump THz probe technique
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通过光泵太赫兹探针技术测量 GaAs、InP 和 Si 中的非线性吸收系数
DOI：
10.1016/j.optcom.2007.01.049
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发表时间：
2007
期刊：
影响因子：
--
通讯作者：
J. Preston
中科院分区：
文献类型：
--
作者：
H. Tiedje;H. Haugen;J. Preston
提出了一种测量半导体载流子迁移率和多光子吸收系数的光抽运太赫兹探测方法。太赫兹探测脉冲被用来检测由光泵浦脉冲产生的瞬态光电导。由于具有大于带隙能量的光子能量的泵浦脉冲而导致的在太赫兹频率下的透射系数的变化被用于确定电子和空穴迁移率的总和。光子能量小于带隙能量的泵浦脉冲的弱非线性吸收产生近似均匀的自由载流子分布。太赫兹透射系数与泵浦能量密度，和迁移率，用于体光电导模型，以确定多光子吸收系数。GaAs、InP和Si在1305 nm处的双光子吸收系数分别为42.5±11，70±18和3.3±0.9cm/GW。我们测定了GaAs和InP在2144 nm处的三个光子吸收系数分别为0.19±0.07和0.22± 0.08cm ~ 3/GW ~ 2。
An optical pump terahertz (THz) probe method for measuring carrier mobility and multiphoton absorption coefficients in semiconductors is demonstrated. A THz probe pulse is used to detect the transient photoconductivity generated by an optical pump pulse. The change in transmission coefficient at THz frequencies due to a pump pulse with photon energy greater than the band gap energy is used to determine the sum of electron and hole mobilities. The weak nonlinear absorption of a pump pulse with photon energy less than the band gap energy produces an approximately uniform free carrier distribution. The THz transmission coefficient vs. pump fluence, and the mobility, are used in a bulk photoconductivity model to determine the multiphoton absorption coefficients. For GaAs, InP and Si we find two photon absorption coefficients at 1305nm of 42.5±11, 70±18 and 3.3±0.9cm/GW, respectively. For GaAs and InP we determine three photon absorption coefficients at 2144nm of 0.19±0.07 and 0.22±0.08cm3/GW2.