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用量子主方程理论研究了量子点-腔耦合系统。为了说明理论模型,分析了一个量子点微柱腔强耦合(SC)实验。经研究发现耦合系统在稳态时抽运产生一个新的强耦合标准,抽运可以抑制或者增强强耦合;腔发射谱双峰结构并不是强耦合的明确特征,它还依赖于非相干抽运。研究表明,强耦合经常出现变相的单峰而弱耦合(WC)出现双峰结构与系统所控制的参数值密切相关。激子抽运增加时,腔发射谱由双峰逐渐变成增宽的单峰最后变成窄的单峰;腔衰减率增加时,均为双峰结构的腔发射光谱经历了从强耦合到弱耦合的转变。量子点腔失谐系统有效耦合强度与非相干抽运密切相关。 相似文献
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本文考虑原子和腔场存在衰减的情况,研究了耦合 腔系统中两子系统间的几何量子失谐。在原子和腔场衰减系数相等的特殊情况下,通过解薛 定谔方程,给出了系统态矢演化规律。采用数值计算方法,讨论了原子和腔场衰减对两子系 统间几何量子失谐的影响。研究结果表明:两原子间、两腔场间、以及原子和腔场之间的几 何量子失谐都呈现出振幅衰减式振荡,直至衰减至零;并且,随衰减系数增大,衰减加快。 相似文献
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推导出一个关于 结构密度矩阵的量子失协的表达式。在单一激发下,给出两个非耦合的量子比特分别与库相互作用构成的系统的动力学的精确解,然后用非马尔科夫主方程方法精确求解了这个系统的耗散动力学。在失谐光谱密度下,讨论和比较不同耦合区域内系统的量子失协动力学特征。结果表明:量子失协表达式适用于任意有 型密度矩阵的物理系统,在失谐光谱密度下,证实两类主方程分别适用于不同的耦合区域。这将为以后更加简便地计算量子失协,以及在不同的耦合区域运用哪一类主方程提供一定的参考依据。 相似文献
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提出了一种基于光子-超导量子比特-声子三体复合量子系统相互作用的方案,具体由微波腔和微机械谐振器共同耦合一个超导电荷量子比特构成.基于抽运-探测方法,利用量子朗之万演化方程获得系统一阶线性极化率,研究了超导量子比特耦合微波腔和机械谐振器系统的吸收特性.结果 表明,利用双场探测手段,根据信号场的吸收谱中双峰之间的宽度可以... 相似文献
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讨论了一种一维准周期系统的输运性质.该系统由一系列Fibonacci耦合的量子点组成.利用转移矩阵方法并考虑实验技术,推导了通过一系列量子点的电子透射几率,从而讨论了电导与磁场和电压的关系.通过数字计算获得了具有非常丰富结构的透射谱,这种结构的丰富性依赖于量子点间的耦合. 相似文献
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利用原子-腔超强耦合光力系统,通过调制光力耦合,开展了力学振子的宏观量子叠加态的制备与特性研究。首先利用Wei-Norm方法给出了演化算符的计算过程,并针对任意原子-腔初始态情况,给出了整个系统演化波函数的解析形式,结果表明假设对原子―腔子系统进行测量,在一定条件下,振子将处于宏观量子叠加态。进一步给出了力学振子宏观量子叠加态的Wigner函数的解析表达式,并对影响宏观量子态量子性的可能因素进行了理论计算和分析。最后讨论了原子-腔不同的初始态对宏观量子相干性强弱的影响,并给出宏观量子相干性最强的初态参数;还讨论了原子-腔耦合强度对宏观量子叠加态的量子相干性的影响,发现耦合强度越强,宏观量子叠加态的量子相干性就越强。 相似文献
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推导了共腔双区激光器的外量子效率,计算了GaAs-Al_(0.3)Ga_(0.7)As DH共腔双区激光器的外量子效率与注入电流的关系.测量了GaAs一Al_(0.3)Ga_(0.7)As DH共腔双区波导激光器的外量子效率,实验结果和理论分析基本一致. 相似文献
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提出了二能级原子与双模光场耦合系统的纠缠纯化方案,并对系统纯化前后量子传输保真度进行了研究.研究表明:通过调整两个量子逻辑门的旋转角度,可以有效地改进相位阻尼和失谐对量子传输保真度的影响,并且获得了通过纯化后的信道进行传输的最大保真度. 相似文献
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Transverse Mode Switching and Locking in Vertical-Cavity Surface-Emitting Lasers Subject to Orthogonal Optical Injection 总被引:1,自引:0,他引:1
Valle A. Gatare I. Panajotov K. Sciamanna M. 《Quantum Electronics, IEEE Journal of》2007,43(4):322-333
In this paper, we report on theoretical and experimental investigation on polarization and transverse mode behavior of vertical-cavity surface-emitting lasers (VCSELs) under orthogonal optical injection as a function of the injection strength and of the detuning between the injection frequency and the free-running frequency of the solitary laser. As the injection strength increases the VCSEL switches to the master laser polarization. We find that the injection power necessary to obtain such polarization switching is minimum at two different values of the frequency detuning: the first one corresponds to the frequency splitting between the two linearly polarized fundamental transverse modes, and the second one appears at a larger positive frequency detuning, close to the frequency difference between the first-order and the fundamental transverse modes of the solitary VCSEL. We show theoretically that both the depth and the frequency corresponding to the second minimum increase when the relative losses between the two transverse modes decrease. Bistability of the polarization switching is obtained for the whole frequency detuning range. Such a bistability is found for the fundamental mode only or for both transverse modes, depending on the value of the detuning. The theoretical and experimental optical spectra are in good agreement showing that the first-order transverse mode appears locked to the external injection 相似文献
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Detailed theoretical analysis of the size fluctuation in InAs-GaAs quantum dot (QD) lasers is presented. Analytical expressions for the inhomogeneous line broadening and the optical gain are derived for a Gaussian size fluctuation distribution. The effect of size fluctuations on the QD carrier density, modal gain, and differential gain is studied. Red shifts in the gain peak is observed when size fluctuations increases. The energy detuning between the gain peak and the differential gain peak for a pyramidal quantum dot system having an average base length of 130 /spl Aring/ and standard deviation of 7 /spl Aring/ is about 12 meV. 相似文献
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提出一个在腔QED中产生cluster-type的纠缠相干态的方案。基于三能级Λ型原子和双模腔场之间的大失谐相互作用下,原子的自发辐射可以被忽略。此外,腔场的初态是真空态。在这个方案中,对原子进行测量后,能够产生腔场的cluster型的纠缠相干态,并讨论了实验的可行性。 相似文献
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In the context of cavity quantum electrodynamics (QED), a potential scheme is proposed to generate entangled coherent states. The scheme includes twice interactions of two-level atoms with cavities. In the first interaction, two atoms are sent into a microwave cavity with the large detuning respectively. And then the second interaction is that the two atoms enter another microwave cavity and are driven by a resonant classical field meantime. When we choose the proper interaction time and make measurement on the two atoms, the two microwave cavity mode fields are determinatively entangled. In addition, it is easy to generalize the scheme to multi-cavity and multi-atom. 相似文献
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N. A. Maleev A. E. Zhukov A. R. Kovsh A. Yu. Egorov V. M. Ustinov I. L. Krestnikov A. V. Lunev A. V. Sakharov B. V. Volovik N. N. Ledentsov P. S. Kop’ev Zh. I. Alfërov D. Bimberg 《Semiconductors》1999,33(5):586-589
Semiconductor heterostructures with vertical optical cavities with active regions, based on arrays of InAs quantum dots inserted
in an external InGaAs quantum well, have been obtained by molecular-beam epitaxy on GaAs substrates. The dependences of the
reflection and photoluminescence spectra on the structural characteristics of the active region and optical cavities have
been investigated. The proposed heterostructures are potentially suitable for optoelectronic devices at wavelengths near 1.3
μm.
Fiz. Tekh. Poluprovodn. 33, 629–633 (May 1999) 相似文献
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与Λ型原子互作用的二项式光场的量子特性 总被引:1,自引:0,他引:1
运用全量子理论,研究了∧型三能级原子与二项式光场相互作用过程中光场的量子特性;讨论了∧型三能级原子初始状态和二项式光场系数对光场压缩和二阶相干度特性的影响.在选择较小的原子失谐量γ和二项式光场系数η时,光场表现为光子聚束效应和反聚束效应交替出现,若上述参量较大时,光场呈现完全的反聚束效应;适当选取△和η,在一定时域内耦合系统光场的X<,1分量将呈现出压缩效应.表明二项式光场与∧型三能级原子作用时,光场在一定条件下将处于压缩态,且可呈现出持续的反聚束特性. 相似文献
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This paper presents a theory describing coupled optical resonant cavities by means of systems of time-dependent coupled equations for the field amplitudes of standing waves in each resonator. The coupling coefficients entering the theory are derived from first principles. To the author's knowledge, this theory is new. The coupling coefficients can approximately be related to the amplitude transmission coefficients of traveling waves passing between the two resonant cavities. This relationship is checked for an example. Finally, we show that the mode amplitudes of one cavity can be eliminated so that the field in the other cavity becomes coupled to samples of itself taken at earlier times. The coupled-cavity theory applies to cavities with loss or gain. It is here expressed in scalar approximation, but it can easily be extended to vector fields. 相似文献