An Autler-Townes（AT） spectroscopy based on phase conjugate six-wave mixing（SWM） is proposed to detect AT doublet of high-lying state in a Doppler-broadened cascade four-level system.It is found that the SWM spectr...An Autler-Townes（AT） spectroscopy based on phase conjugate six-wave mixing（SWM） is proposed to detect AT doublet of high-lying state in a Doppler-broadened cascade four-level system.It is found that the SWM spectrum is dependent strongly on the ratios between the magnitudes of the wave vectors.We discuss how the Doppler broadening affects the SWM spectrum from a time-domain viewpoint and find that,due the atomic motion,the atomic polarizations acquire different phases for atoms with different velocities as time evolves.The Doppler free SWM spectrum can be obtained only when the atomic polarization can be rephasing again at certain time after the interactions of all the incident fields.展开更多
We show the enhancement and suppression of a six-wave mixing （SWM） signal in the electromagnetically induced transparency in a five-level SSRb atomic system. The results show the Autler-Townes splitting and the enha...We show the enhancement and suppression of a six-wave mixing （SWM） signal in the electromagnetically induced transparency in a five-level SSRb atomic system. The results show the Autler-Townes splitting and the enhancement or suppression of SWM, which are caused respectively by a self-dressing effect and by an external dressing effect in the presence of mutual dressing between two SWM signals. In addition, we observe the polarization dependence of the enhancement and suppression of the SWM signals.展开更多
We study phase-conjugate six-wave mixing spectroscopy based on electromagnetically-induced-transparency in a Doppler-broadened folded four-level system. It is found that the six-wave mixing spectrum can be either Dopp...We study phase-conjugate six-wave mixing spectroscopy based on electromagnetically-induced-transparency in a Doppler-broadened folded four-level system. It is found that the six-wave mixing spectrum can be either Doppler-free or very broad, depending on whether the interference between the polarisations of atoms with different velocities is constructive or destructive. To obtain the Doppler-free six-wave mixing spectrum in the folded four-level system, the conditions are more stringent in comparison with those in the cascade and N-type four-level systems. This polarisation interference can be controlled in the presence of a strong coupling field.展开更多
We have investigated the dressed effects of non-degenerate four-wave mixing （NDFWM） and demonstrated a phase-sensitive method of studying the fifth-order nonlinear susceptibility due to atomic coherence in RN-type f...We have investigated the dressed effects of non-degenerate four-wave mixing （NDFWM） and demonstrated a phase-sensitive method of studying the fifth-order nonlinear susceptibility due to atomic coherence in RN-type four-level system. In the presence of a strong coupling field, NDFWM spectrum exhibits Autler-Townes splitting, accompanied by either suppression or enhancement of the NDFWM signal, which is directly related to the competition between the absorption and dispersion contributions. The heterodyne-deteeted nonlinear absorption and dispersion of six-wave mixing signal in the RN-type system show that the hybrid radiation-matter detuning damping oscillation is in the THz range and can be controlled and modified through the eolour-locked correlation of twin noisy fields.展开更多
在飞行过程中,弹托要减小对弹体的干扰并实现快速分离,其基本前提是自身结构设计合理。为优化弹托结构设计,本文采用用户自定义函数(User-Defined Functions,UDF)和动网格技术,耦合计算流体力学和六自由度(Six Degrees of Freedom,6DOF...在飞行过程中,弹托要减小对弹体的干扰并实现快速分离,其基本前提是自身结构设计合理。为优化弹托结构设计,本文采用用户自定义函数(User-Defined Functions,UDF)和动网格技术,耦合计算流体力学和六自由度(Six Degrees of Freedom,6DOF)外弹道方程,通过仿真计算了尾翼稳定脱壳穿甲弹在不同弹托结构下的弹托分离过程,得到了弹托分离过程流场的演变情况、弹托与弹体之间的激波和气流相互耦合作用效果、弹托的6DOF轨迹参数及其对弹体各项气动力和力矩系数的影响规律。结果表明:长弹托的脱壳过程相对平稳,轴向运动较弱,同时刻弹托俯仰角更小,前腔面积较大时分离后期翻转和偏航运动更加突出,中腔面积对弹托运动影响较小;适当减小弹托长度、增大前腔面积和减小中腔面积可有效减小对弹体气动力和力矩系数的扰动,加快弹托分离,提高弹体的飞行稳定性。展开更多
基金Project supported by the National Basic Research Program of China(Grant No.2013CB922002)the National Natural Science Foundation of China(Grant Nos.11274376 and 61308011)the National High Technology Research and Development Program of China(Grant No.2011AA120102)
文摘An Autler-Townes（AT） spectroscopy based on phase conjugate six-wave mixing（SWM） is proposed to detect AT doublet of high-lying state in a Doppler-broadened cascade four-level system.It is found that the SWM spectrum is dependent strongly on the ratios between the magnitudes of the wave vectors.We discuss how the Doppler broadening affects the SWM spectrum from a time-domain viewpoint and find that,due the atomic motion,the atomic polarizations acquire different phases for atoms with different velocities as time evolves.The Doppler free SWM spectrum can be obtained only when the atomic polarization can be rephasing again at certain time after the interactions of all the incident fields.
基金Project supported by the National Natural Science Foundation of China (Grant Nos.10974151,61078002,and 61078020)the Program for New Century Excellent Talents in University of Ministry of Education of China (Grant No.08-0431)the Cross-Disciplinary Project of Xi'an Jiaotong University,China (Grant Nos.2009xjtujc08,XJJ20100100,and XJJ20100151)
文摘We show the enhancement and suppression of a six-wave mixing （SWM） signal in the electromagnetically induced transparency in a five-level SSRb atomic system. The results show the Autler-Townes splitting and the enhancement or suppression of SWM, which are caused respectively by a self-dressing effect and by an external dressing effect in the presence of mutual dressing between two SWM signals. In addition, we observe the polarization dependence of the enhancement and suppression of the SWM signals.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 10774185,10974252,and 10674174)the National Program for Basic Research in China (Grant No. 2006CB921107)
文摘We study phase-conjugate six-wave mixing spectroscopy based on electromagnetically-induced-transparency in a Doppler-broadened folded four-level system. It is found that the six-wave mixing spectrum can be either Doppler-free or very broad, depending on whether the interference between the polarisations of atoms with different velocities is constructive or destructive. To obtain the Doppler-free six-wave mixing spectrum in the folded four-level system, the conditions are more stringent in comparison with those in the cascade and N-type four-level systems. This polarisation interference can be controlled in the presence of a strong coupling field.
基金Project supported by the National Natural Science Foundation of China （Grant Nos 60308002 and 60678005）, the Foundation for the Author of National Excellent Doctoral Dissertation of China （Grant No 200339）, the Research Foundation from Ministry of Education of China （Grant No 105156）, the For Ying-Tong Education Foundation for Young Teachers of Higher Education Institutions of China （Grant No 101061） and the Specialized Research Fund for the Doctoral Program of Higher Education of China （Grant No 20050698017）.
文摘We have investigated the dressed effects of non-degenerate four-wave mixing （NDFWM） and demonstrated a phase-sensitive method of studying the fifth-order nonlinear susceptibility due to atomic coherence in RN-type four-level system. In the presence of a strong coupling field, NDFWM spectrum exhibits Autler-Townes splitting, accompanied by either suppression or enhancement of the NDFWM signal, which is directly related to the competition between the absorption and dispersion contributions. The heterodyne-deteeted nonlinear absorption and dispersion of six-wave mixing signal in the RN-type system show that the hybrid radiation-matter detuning damping oscillation is in the THz range and can be controlled and modified through the eolour-locked correlation of twin noisy fields.
文摘在飞行过程中,弹托要减小对弹体的干扰并实现快速分离,其基本前提是自身结构设计合理。为优化弹托结构设计,本文采用用户自定义函数(User-Defined Functions,UDF)和动网格技术,耦合计算流体力学和六自由度(Six Degrees of Freedom,6DOF)外弹道方程,通过仿真计算了尾翼稳定脱壳穿甲弹在不同弹托结构下的弹托分离过程,得到了弹托分离过程流场的演变情况、弹托与弹体之间的激波和气流相互耦合作用效果、弹托的6DOF轨迹参数及其对弹体各项气动力和力矩系数的影响规律。结果表明:长弹托的脱壳过程相对平稳,轴向运动较弱,同时刻弹托俯仰角更小,前腔面积较大时分离后期翻转和偏航运动更加突出,中腔面积对弹托运动影响较小;适当减小弹托长度、增大前腔面积和减小中腔面积可有效减小对弹体气动力和力矩系数的扰动,加快弹托分离,提高弹体的飞行稳定性。
基金Supported by the Program for the National Natural Science Foundation of China(51101022)Key Science and Technology Program of Shaanxi Province of China(2013K06-27)
