Intersubband absorption with difference-frequency generation in GaAs asymmetric quantum wells |
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Authors: | Cao Xiao-Long Li Zhong-Yang Yao Jian-Quan Wang Yu-Ye Zhu Neng-Nian Zhong Kai Xu De-Gang |
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Institution: | a College of Precision Instrument and Opto-electronics Engineering, Institute of Laser and Opto-electronics, Tianjin University, Tianjin 300072, China;b Institute of Electric Power, North China University of Water Resources and Electric Power, Zhengzhou 450011, China;c Key Laboratory of Opto-electronics Information Technology (Tianjin University), Ministry of Education, Tianjin 300072, China |
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Abstract: | An asymmetric quantum well (AQW) is designed to emit terahertz (THz) waves by using difference frequency generation (DFG) with the structure of GaAs/Al0.2Ga0.8As/Al0.5Ga0.5As. The characteristics of absorption coefficients are analysed under the parabolic and non-parabolic energy-band conditions in detail. We find that the absorption coefficients vary with the two pump optical intensities, and they reach the maxima when the pump wavelengths are given as λ p1=9.70 μm and λ p2=10.64 μm respectively. Compared with non-parabolic condition, the total absorption coefficient under parabolic condition shows a blue shift, which is due to the increase in the energy difference between the ground and excited states. By adjusting the two pump optical intensities, the wave vector phase-matching condition inside the AQW is satisfied. |
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Keywords: | asymmetric quantum wells absorption coefficient THz-wave phase-matching |
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