The Effect of Incoherent Population Pumping on Squeezing in Resonance Fluorescence

1　ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｓｑｕｅｅｚｅｄｓｔａｔｅｓｏｆｒａｄｉａｔｉｏｎｆｉｅｌｄｈａｓｂｅｅｎｅｘｔｅｎｓｉｖｅｌｙｉｎｖｅｓｔｉｇａｔｅｄ[1].Ｂｏｔｈｔｈｅｏｒｅｔｉｃａｌａｎｄｅｘｐｅｒｉｍｅｎｔａｌｓｔｕｄｉｅｓｈａｖｅｓｈｏｗｎｔｈａｔｔｈｅｒｅｓｏｎａｎｃｅｆｌｕｏｒｅｓｃｅｎｃｅｏｆａｄｒｉｖｅｎａｔｏｍｃａｎｓｅｒｖｅａｓａｓｏｕｒｃｅｏｆｎｏｎｃｌａｓｓｉｃａｌｌｉｇｈｔ.Ｆｏｒｅｘａｍｐｌｅ,ＣａｒｍｉｃｈａｅｌａｎｄＷａｌｌｓ,ａｎｄＫｉｍｂｌｅａｎｄＭａｎｄｅｌ[2…     

电子俘获材料的红外最小可激发阈值

A study is made of the steady-state populations of a three-level ladder atom in a squeezed vacuum, driven by a superposition of a monochromatic laser wave with incoherent population pumping. Using the density matrix equations for the system, the steady-state populations are calculated numerically and shown graphically as functions of two-photon detuning for various cases of the squeezed vacuum and different incoherent pump rates. It is shown that the incoherent population pumping tends to greatly decrease the two-photon absorption from the squeezed vacuum.     

Steady state Behaviour of a Three level Ladder Atomic System with Incoherent Population Pumping in a Squeezed Vacuum

１ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｒａｄｉａｔｉｖｅｐｒｏｐｅｒｔｉｅｓｏｆａｔｏｍｉｃｓｙｓｔｅｍｓｉｎａｓｑｕｅｚｅｄｖａｃｕｕｍｈａｖｅｂｅｎｔｈｅｓｕｂｊｅｃｔｏｆｉｎｔｅｎｓｅｉｎｖｅｓｔｉｇａｔｉｏｎｏｖｅｒｔｈｅｐａｓｔｄｅｃａｄｅ．Ａｓ...     

Effect of Quantum Interference from Incoherent Pumping Field and Spontaneous Emission on Controlling the Optical Bistability and Multi-Stability

Optical bistability (OB) and optical multi-stability (OM) of a four-level Λ-type atomic system with two fold lower levels inside a unidirectional ring cavity is investigated. The effect of quantum interference arising from spontaneous emission and incoherent pumping on OB and OM is discussed. It is found that the threshold of OB and OM can be controlled by quantum interference mechanisms. In addition intensity of coupling field and the rate of an incoherent pumping field on behavior of OB and OM are then discussed.     

Impact of Interacting Quantum Coherence via Decays and Incoherent Pumping on Transient and Steady-State Behaviors of Absorption

The effects from quantum coherence via decays and incoherent pumping on the lasing without inversion(LWI) are investigated in a four-level system.By analyzing the transient and steady-state behaviors of the absorption,we find that the gain occurs when both spontaneously generated coherence(SGC) and coherence induced by incoherent pumping(IPC) are considered.We attribute the occurrence of the gain to the interaction of quantum coherence via decays and incoherent pumping.     

用非相干光激发布居光栅技术研究物质的纵向弛豫过程

详细分析了用非相干光时延四波混频研究物质纵向弛豫过程的原理和技术关键，从实验上测定了几种染料分子的纵向弛豫时间并作了讨论。     

The squeezing dynamics of two independent atoms by detuning in two non-Markovian environments

The squeezing dynamics of two independent two-level atoms off-resonantly coupled to two non-Markovian reservoirs is studied by the time-convolutionless master-equation approach. We find that the squeezing of two atoms is dependent on both detuning and the non-Markovian effect. Our results show that, in the non-Markovian regime, the bigger the detuning and the stronger the non-Markovian effect are, the larger the strength of the squeezing is. And the squeezing of two atoms can be effectively protected for a long time when both the non-Markovian effect and detuning are present simultaneously. The physical mechanism is that the detuning not only can promote the feedback of information from the environment into the atomic system but also can greatly suppress the atomic decay in the non-Markovian regime.     

非相干泵浦对原子系统位相相关吸收性质的影响

研究发现在具有真空诱导相干性的开放和封闭ladder 型原子系统中,探测场和驱动场之间相对位相对吸收性质有重要的调制作用,同时非相干泵浦对位相相关的吸收性质有显著的影响.在这两种系统中,通过调节非相干泵浦,可以实现从吸收到增益和从粒子数反转激光到无粒子数反转激光的转化,并可获得最大的无反转激光增益.但是,当非相干泵浦不存在时,对相对位相的任意值,在封闭系统中只出现吸收而不能得到无反转激光增益;然而在开放系统中,对于适当的相对位相值甚至可以产生比有非相干泵浦时更大的无反转激光增益.     

Effect of cavity dissipation on the emission spectrum of an atom interacting with a field in the dispersive approximation

The emission spectrum of a two-level atom interacting dispersively with a single mode radiation field in the dissipative cavity is investigated. A general expression for the emission spectrum is derived. The numerical results for the initial field in coherent state are calculated. It is found that the spectrum structure is influenced significantly by the cavity damping constant \kappa , and the spectrum structure is dependent on the interaction time T when the cavity dissipation is present. Only one peak located at Ω_a appears in the atomic spectra for larger T.     

与运动原子相互作用的场的压缩效应

采用量子光学中时间演化算符方法，研究了与运动原子相互作用的场的压缩效应，揭示了光场的初始平均光子数和场模结构参数对光场压缩特性的影响，结果表明：适当选择系统参数，可获得在时间上持续压缩的压缩光。     

与量子光场相互作用的运动原子的熵压缩

运用量子信息熵理论,研究了与量子光场相互作用的二能级运动原子的熵压缩,讨论了原子运动和场模结构对原子熵压缩的影响,并且比较了分别从基于信息熵测不准关系和海森伯测不准关系出发得出的结果,表明原子的运动导致了原子熵压缩的周期性演化;随着场模结构参量的增大,熵压缩的演化周期缩短,压缩时间延长;选择适当的系统参量,运动原子能够呈现长时间的持续熵压缩效应。当原子反转为零时,基于海伯堡测不准关系的方差压缩定义不再有效,而熵压缩实现了对原子压缩效应的高灵敏量度。     

Squeezing effect of the cavity field in the two-atom Jaynes-Cummings model

Authors investigate the model that two two level atoms interact with a single mode cavity. The formulation of the time evolution operator for the two atom Jaynes Cummings model is presented by the bare states approach. Besides, squeezing effect of the cavity field is studied and some novel features are obtained.     

有损光纤中孤子压缩效应

在线性近似条件下，求解了考虑光纤损耗的量子非线性Schroedinger方程，并用数值法计算了在光纤中孤子的压缩比随传输距离的变化。结果表明，振幅越大，光纤损耗越小，可得到最大压缩程度越大，孤子处于压缩态的距离越长。     

原子间相互作用对双模原子激光压缩性质的影响

研究了由单模压缩相干态光场与Ξ型三能级原子玻色爱因斯坦凝聚体(BEC)相互作用系统中耦合输出的双模原子激光的压缩特性,重点讨论了玻色爱因斯坦凝聚体原子间相互作用对原子激光压缩性质的影响,并讨论了原子激光压缩对光场初始压缩因子的依赖关系。结果表明:由光场诱导的双模原子激光呈现周期性的压缩,原子间的相互作用和光场初始压缩因子对原子的压缩性质具有重要影响。原子间的相互作用影响原子激光压缩的振荡频率而不会影响其压缩深度,而初始光场的压缩因子则对原子激光压缩深度产生调制作用,且初始光场的压缩因子越大,则原子激光压缩的时间越短。     

The Squeezing Effect in a Mesoscopic RLC Circuit

Using the path integral method we derive quantum wave function and quantum fluctuations of charge andcurrent in the mesoscopic RLC circuit. We find that the quantum fluctuation of charge decreases with time, oppositely,the quantum fluctuation of current increases with time monotonously. Therefore there is a squeezing effect in the circuit.If some more charge devices are used in the mesoscopic-damped circuit, the quantum noise can be reduced. We also findthat uncertainty relation of charge and current periodically varies with the period π/2 in the under-damped case.     

Spin Squeezing of the Two Two-Level Atoms Interacting with a Binomial Field

Spin squeezing of the two two-level atoms interacting with a binomial field has been investigated with the different initial conditions. It is shown that spin squeezing can be exhibited in the certain range of p and the degree of squeezing is dependent on p.     

Effects of Atomic Centre-of-mass Motion in T-C Model

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Limits of Noise Squeezing in Kerr Effect

It is well known that the optical Kerr effect can serve as a source of highly squeezed light, however, the analytical limit of the noise suppression has not been found yet. The process is reconsidered and an analytical estimation of the optimal quadrature noise level is found. The validity of the new scaling law is checked numerically and analytically.     

原子在双腔场间的共振隧穿

考虑单个二能级原子穿过2个空间分离的单模腔场,研究原子质心运动的动能、腔长与腔间距对原子透射率的影响。结果表明：当原子的动能比较大时,原子有足够的能量穿透腔场对其的阻挡,此时只有腔长的变化对原子的透射有微小的影响而腔间距的作用则可以忽略;当原子的动能较小时,原子本身的能量小于腔场势垒的能量,此时腔长与腔间距对原子透射率的影响极为明显。     

压缩真空场与原子非线性作用系统中场熵的压缩特性

利用量子信息熵理论,研究了附加克尔介质的压缩真空场与二能级原子依赖强度耦合相互作用系统中场熵的压缩特性.讨论了初始压缩真空场的压缩度以及克尔非线性作用的强度对场熵压缩特性的影响.结果表明,无克尔介质量,场熵压缩的演化具有严格的周期性.克尔介质的非线性作用的强弱可以改变场熵压缩的周期性.在初始压缩真空场的压缩度较大(r=5)时,无论克尔介质作用的强弱如何变化,场熵始终处于被压缩状态.