共查询到19条相似文献,搜索用时 406 毫秒
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研究双模高Q腔场与Λ型三能级原子在大失谐条件下相互作用(即含交流斯塔克位移的非简并拉曼过程)模型的腔场谱.给出了腔场谱的计算公式和原子初态处于激发态而光场处于双模压缩真空态时的数值结果.讨论了光场压缩因子r和交流斯塔克位移参数γ(≡g2/g1) 变化对谱结构的影响.结果表明:①当压缩因子r=0时,原子与双模真空场无耦合;在r>0时,两模均可能呈现单峰或双峰;但r 继续增大只引起峰高增大,并不引起峰位的移动.表明初始场强的变化不改变腔场谱的频率,这与非简并拉曼耦合J-C模型的腔场谱明显不同.②当取r=2而改变γ值时,谱结构会有明显的变化.在γ较小时,模Ⅰ腔场谱为不等高双峰结构,模Ⅱ只有单峰;在γ=1时,两模腔场谱都为双峰结构,四峰高度近似相等;当γ继续增大时,模Ⅰ的双峰逐渐靠近最后合并为单峰,模Ⅱ双峰的裂距缓慢加大但峰高差别迅速增加.(OA6) 相似文献
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含Kerr介质腔中耦合双原子系统的腔场谱 总被引:9,自引:3,他引:6
研究了含Kerr介质腔中耦合双原子与辐射场相互作用模型的腔场谱,给出了初始时刻原子处于激发态、光场处于光子数态时的计算结果,讨论了Kerr效应对谱结构的影响。结果发现,随Kerr效应增强,各峰频率不断升高;Rabi峰一般为4峰结构,其中2峰强度逐渐减弱直至消失,另2峰在χ/g=0.7附近有唯一极大值点,腔场谱演化为双峰结构,其频差不断增大;当n>0时,只有1峰强度单调升高直至饱和,其余各峰强度均单调减弱直至消失,腔场谱最终演化为高频的单峰结构。 相似文献
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基于量子回归理论建立了微腔-量子点耦合模型的主方程,研究了用激光脉冲激发时微腔中的量子点二能级系统的密度矩阵随时间的演化,然后通过密度矩阵得出发射光子数和二阶相关度等特性,并对适合于制作单光子源的微腔参数和泵浦条件进行了优化。相关参数中,微腔衰退率和系统耦合系数的相对关系对单光子发射过程起关键作用。 相似文献
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为了深入研究光抽运垂直外腔面发射激光器的增益特性,以InGaAs/GaAs应变量子阱系统为例,建立了将带隙、带边不连续性计算和带结构计算系统结合起来的完整体系,考虑在应变影响下能带及波函数的混合效应。利用有限差分法对含6×6 Luttinger-Kohn哈密顿量的有效质量方程精确求解,得到了InGaAs/GaAs应变量子阱导带、价带的能带结构和包络函数,然后选用Lorentzian线形函数,数值模拟了量子阱的材料增益谱和自发辐射谱。最后讨论了阱宽、载流子浓度、温度等因素对量子阱材料增益的影响,为光抽运垂直外腔面发射激光器的优化设计提供了理论依据。 相似文献
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研究了MOCVD生长的具有双发射峰结构的InGaN/GaN多量子阱发光二极管(LED)的结构和发光特性.在透射电子显微镜(TEM)下可以发现量子阱的宽度不一致,电致发光谱(EL)发现了位于2.45eV的绿光发光峰和2.81eV处的蓝光发光峰.随着电流密度增加,双峰的峰位没有移动,直到注入电流密度达到2×104 mA/cm2时,绿光发光峰发生蓝移,而蓝光发光峰没有变化.单色的阴极荧光谱(CL)发现绿光发射对应的发光区包括絮状区域和发光点,而蓝光发射对应的发光区仅包含絮状区域.通过以上的结果,我们认为蓝光发射基本上源于InGaN量子阱发光,而绿光发射则起源于量子阱和量子点的发光. 相似文献
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研究了MOCVD生长的具有双发射峰结构的InGaN/GaN多量子阱发光二极管(LED)的结构和发光特性.在透射电子显微镜(TEM)下可以发现量子阱的宽度不一致,电致发光谱(EL)发现了位于2.45eV的绿光发光峰和2.81eV处的蓝光发光峰.随着电流密度增加,双峰的峰位没有移动,直到注入电流密度达到2×104 mA/cm2时,绿光发光峰发生蓝移,而蓝光发光峰没有变化.单色的阴极荧光谱(CL)发现绿光发射对应的发光区包括絮状区域和发光点,而蓝光发射对应的发光区仅包含絮状区域.通过以上的结果,我们认为蓝光发射基本上源于InGaN量子阱发光,而绿光发射则起源于量子阱和量子点的发光. 相似文献
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傅恩生 《激光与光电子学进展》2005,42(1):58-58
很多研究人员,根据微机电系统原理大胆开发出波长可调谐垂直腔面发射激光器(VCSEL),作为光纤远程通信系统的光源。虽然至今大多数工作集中在悬臂梁结构,但美国加州Fremont的一个工程师小组,最近用桥结构对称抽运光模型(不耦合到芯)制成了微机电系统波长可调谐垂直腔面发射激光器。 相似文献
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Chen Shihua 《半导体学报》2010,31(5)
On the condition of electric-longitudinal-optical (LO) phonon strong coupling in both two- and threedimensional parabolic quantum dots (QDs),we obtain the eigenenergies of the ground state (GS) and the first excited state (ES),the eigenfunctions of the GS and the first ES by using a variational method of Pekar type.This system in QD may be employed as a quantum system-quantum bit (qubit).When the electron is in the superposition state of the GS and the first ES,we obtain the time evolution of the electron density.The relations of both the electron probability density and the period of oscillation with the electric-LO phonon coupling strength and confinement length are discussed. 相似文献
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在外电场的作用下,同时抛物量子点中电子-声子强耦合的条件下,由于电子-声子的相互作用和外界温度的影响,使电子在基态吸收一个声子的能量跃迁到激发态。采用Pekar变分方法,讨论电子的基态能量、外电场、量子点的受限长度、电子-声子耦合强度和外界温度对电子跃迁速率的影响。结果表明,外界温度对电子跃迁速率的影响起主导作用,在确定的温度下,电子的基态能量越大跃迁速率越小。同时,电子跃迁速率随着电子-声子耦合强度的增加而变大,随着外电场、量子点的受限长度的增大,电子跃迁速率先减小后变大。 相似文献
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Dynamics of Strong Coupling between J‐Aggregates and Surface Plasmon Polaritons in Subwavelength Hole Arrays 下载免费PDF全文
Hai Wang Hai‐Yu Wang Angelo Bozzola Andrea Toma Simone Panaro Waseem Raja Lei Wang Qi‐Dai Chen Huai‐Liang Xu Francesco De Angelis Hong‐Bo Sun Remo Proietti Zaccaria 《Advanced functional materials》2016,26(34):6198-6205
A prototypical hybrid system formed by strong coupled gold hole arrays and J‐aggregate molecules is investigated by using both steady‐state spectroscopic method and ultrafast pump‐probe approach. In particular, the plasmonic response of the device has been tuned by modifying its periodicity thus to achieve the strongest possible coupling regime. It is found that in the transient absorption spectra, under upper band excitation, the bleaching signal from uncoupled J‐aggregate molecules completely disappears. Instead, two distinctive period dependent bleaching bands are formed, clearly fingerprint of the hybrid exciton‐plasmon state. The dynamics of these bands is also directly analyzed. A remarkable long lifetime is found especially for the upper band, corresponding to the presence of a trap state in its transient absorption spectra under resonance excitation. Such unique feature should provide a new approach to control quantum‐mechanical states under coherent coupling. 相似文献
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通过求解Milburn 方程,研究了包含非线性相互作用的Heisenberg自旋链模型中量子纠缠和平均保真度的动力学特性,讨论了非线性相互作用和不同的初始态对量子纠缠以及平均保真度退相干的影响。研究发现,系统处于铁磁或者反铁磁的不同会导致量子纠缠随非线性相互作用的变化有极大的差异,相互作用处于铁磁情形时的纠缠变化比反铁磁时的纠缠变化更明显。研究还发现, 不同的初始态对应不同的平均保真度表现,初始态的选择会影响到系统的量子通信特性。 相似文献
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Herda R. Liem A. Schnabel B. Drauschke A. Fuchs H.-J. Kley E.-B. Zellmer H. Tuennermann A. 《Electronics letters》2003,39(3):276-277
A report is presented of a novel side-coupling method of high-power single stripe diode lasers into double-clad fibres. Grating design considerations and experimental results with high coupling efficiencies are presented. The scalability of this method is shown by incoherent superposition of several pump diodes in a fibre laser. 相似文献
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Jürgen Mony Clàudia Climent Anne Ugleholdt Petersen Kasper Moth-Poulsen Johannes Feist Karl Börjesson 《Advanced functional materials》2021,31(21):2010737
Strong exciton-photon coupling is achieved when the interaction between molecules and an electromagnetic field is increased to a level where they cannot be treated as separate systems. This leads to the formation of polaritonic states and an effective rearrangement of the potential energy surfaces, which opens the possibility to modify photochemical reactions. This work investigates how the strong coupling regime is affecting the photoisomerization efficiency and thermal backconversion of a norbornadiene–quadricyclane molecular photoswitch. The quantum yield of photoisomerization shows both an excitation wavelength and exciton/photon constitution dependence. The polariton-induced decay and energy transfer processes are discussed to be the reason for this finding. Furthermore, the thermal back conversion of the system is unperturbed and the lower polariton effectively shifts the absorption onset to lower energies. The reason for the unperturbed thermal backconversion is that it occurs on the ground state, which is unaffected. This work demonstrates how strong coupling can change material properties towards higher efficiencies in applications. Importantly, the experiments illustrate that strong coupling can be used to optimize the absorption onset of the molecular photoswitch norbonadiene without affecting the back reaction from the uncoupled quadricyclane. 相似文献