共查询到20条相似文献,搜索用时 15 毫秒
1.
Excitation power-dependent micro-photoluminescence spectra and photon-correlation measurement are used to study the optical properties and photon statistics of single InAs quantum dots. Exciton and biexciton emissions, whose photoluminescence intensities have linear and quadratic excitation power dependences, respectively, are identified. Under pulsed laser excitation, the zero time delay peak of second order correlation function corresponding to exciton emission is well suppressed, which is a clear evidence of single photon emission. 相似文献
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We report on the single photon emission from single InAs/GaAs self-assembled Stranski-Krastanow quantum dots up to 80 K under pulsed and continuous wave excitations. At temperature 8OK, the second-order correlation function at zero time delay, g^(2)(0), is measured to be 0.422 for pulsed excitation. At the same temperature under continuous wave excitation, the photon antibunching effect is observed. Thus, our experimental results demonstrate a promising potential application of self-assembled InAs/GaAs quantum dots in single photon emission at liquid nitrogen temperature. 相似文献
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We investigate the growth of strain-engineered low-density 1hAs bilayer quantum dots (BQDs) on GaAs by molecular beam epitaxy. Owing to increasing dot size and In composition of the upper QDs, low-density BQDs in a GaAs matrix with an emission wavelength up to 1.4 μm at room temperature are achieved. Such a wavelength is larger than that of conventional QDs in a GaAs matrix (generally of about 1.3μm). The optical properties of the BQDs are sensitive to annealing temperature used after spacer layer growth. Significant decrease of integrated PL intensity is observed as the annealing temperature increases. At 10 K, single photon emission from the BQDs with wavelength around 1.3μm is observed. 相似文献
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The statistic properties of photon emissions from single
semiconductor quantum dots with V-type level driven by pulses are
investigated theoretically. Based on quantum regression theorem and master
equations, the dynamic equations of the second-order correlation function of
the photon emissions are deduced. The calculated results reveal that the
efficiency of single photon emissions from two orthogonal polarization
eigenstates |x〉and
|y〉) reaches the maximum
when the input pulses area is about π, and the probability of the
cross-polarized single photon emission from |x 〉 and
|y 〉decreases with increasing of pulse width. 相似文献
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LIU Wen-Juan LI Yao-Yi 《理论物理通讯》2008,50(12):1417-1421
The statistic properties of photon emissions from single semiconductor quantum dots with V-type level driven by pulses are investigated theoretically. Based on quantum regression theorem and master equations, the dynamic equations of the second-order correlation function of the photon emissions are deduced. The calculated results reveal that the efficiency of single photon emissions from two orthogonal polarization eigenstates (|x) and |y) ) reaches the maximum when the input pulses area is about π, and the probability of the cross-polarized single photon emission from |x) and |y) decreases with increasing of pulse width. 相似文献
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XIEWen-Fang ZHUWu 《理论物理通讯》2003,40(1):113-116
The energy spectra of low-lying states of an exciton in a single and a vertically coupled quantum dots are studied under the influence of a perpendicularly applied magnetic field. Calculations are made by using the method of numerical diagonalization of the Hamiltonian within the effective-mass approximation. We also calculated the binding energy of the ground and the excited states of an exciton in a single quantum dot and that in a vertically coupled quantum dot as a function of the dot radius for different vaJues of the distance and the magnetic field strength. 相似文献
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Single Photon Scattering in a Pair of Waveguides Coupled by a Whispering-Gallery Resonator Interacting with a Semiconductor Quantum Dot 下载免费PDF全文
《中国物理快报》2016,(2)
The single photon scattering properties in a pair of waveguides coupled by a whispering-gallery resonator interacting with a semiconductor quantum dot are investigated theoretically.The two waveguides support four possible ports for an incident single photon.The quantum dot is considered a V-type system.The incident direction-dependent single photon scattering properties are studied and equal-output probability from the four ports for a single photon incident is discussed.The influences of backscattering between the two modes of the whispering-gallery resonator for incident direction-dependent single photon scattering properties are also presented. 相似文献
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The energy spectra of low-lying states of an exciton in a single and a vertically coupled quantum dots arestudied under the influence of a perpendicularly applied magnetic field. Calculations are made by using the method ofnumerical diagonalization of the Hamiltonian within the effective-mass approximation. We also calculated the bindingenergy of the ground and the excited states of an exciton in a single quantum dot and that in a vertically coupledquantum dot as a function of the dot radius for different values of the distance and the magnetic field strength. 相似文献
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Using analytical expressions for the polarization field in GaN quantum dot, and an approximation by separating the potential into a radial and an axial, we investigate theoretically the quantum-confined Stark effects. The electron and hole energy levels and optical transition energies are calculated in the presence of an electric field in different directions. The results show that the electron and hole energy levels and the optical transition energies can cause redshifts for the lateral electric field and blueshifts for the vertical field. The rotational direction of electric field can also change the energy shift. 相似文献
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A. Drezet 《Foundations of Physics Letters》2006,19(5):459-470
In the paper with the above title [1] (but without the question mark), it is claimed that quantum nonlocality can be revealed
in a simple interferometry experiment using only single particle. A critical analysis of the concept of hidden variable used
by the authors of [1] shows that the reasoning is not correct. 相似文献
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Temperature effect on the spin pump in a single quantum dot (QD) connected to Normal (NM) and/or Ferromagnetic (FM) leads is investigated with the help of master equation method. Results show that the magnitude and the direction of the temperature difference between the source (L) and drain (R) leads have great impact on the spin current processes. In practical devices, the thermal bias is quite general and then our results may be useful in quantum information processing and spintronics. 相似文献
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Temperature effect on the spin pump in a single quantum dot(QD) connected to Normal(NM) and/or Ferromagnetic(FM) leads is investigated with the help of master equation method. Results show that the magnitude and the direction of the temperature difference between the source(L) and drain(R) leads have great impact on the spin current processes. In practical devices, the thermal bias is quite general and then our results may be useful in quantum information processing and spintronics. 相似文献
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Using measurements pertaining to a suitable Mach-Zehnder (MZ) type setup, a curious quantum mechanical effect of contextuality
between the path and the polarization degrees of freedom of a polarized photon is demonstrated, without using any notion of
realism or hidden variables—an effect that holds good for the product as well as the entangled states. This form of experimental
context-dependence is manifested in a way such that at either of the two exit channels of the MZ setup used, the empirically verifiable subensemble statistical properties obtained by an arbitrary polarization measurement depend upon the choice of a commuting (comeasurable)
path observable, while this effect disappears for the whole ensemble of photons emerging from the two exit channels of the MZ setup. 相似文献
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Single photon detection (SPD) with high quantum efficiency has been widely used for measurement of different quantum states with different photon distributions.Based on the direct single SPD and double-SPD of HBT configuration, we discuss the effect of a real SPD on the photon statistics measurement and it shows that the measured photon distributions for different quantum states are corrected in different forms.The results are confirmed by experiment with the strongly attenuated coherent light and thermal light.This system can be used to characterize the photon statistics of the fluorescence light from single atom or single molecular. 相似文献
18.
Yi-Fu Yu Wei-Ping Li Ji-Wen Yin Jing-Lin Xiao 《International Journal of Theoretical Physics》2011,50(11):3322-3328
On the condition of electric-LO phonon strong coupling in parabolic quantum dot, we obtain the eigenenergies of the ground
state and the first-excited state, the eigenfunctions of the ground state and the first-excited state by using variational
method of Pekar type. This system in quantum dot may be employed as a two-level quantum system-qubit. The phonon spontaneous
emission causes the decoherence of the qubit. We displayed the density matrix of the qubit decayed with the time evolution
and the coherence term of the density matrix element p
10 (or p
01) decayed with the time evolution for different coupling strength, the confinement length, the coefficient dispersion. 相似文献
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本文提出一种基于电子-电子自旋交换相互作用获得自旋极化电流的模型.该方案中,需要两个距离相近的量子点.其中一个是开放系统,另一个是封闭系统.开放系统能完成单电子输运,封闭系统产生比较强的局域磁场,两个系统之间有电子-电子自旋交换相互作用.该相互作用会影响电子输运,从而可以对电子输运产生自旋过滤效应.我们用量子主方程描述开放系统的演化,在有效哈密顿量的基础上,可以得到解析结果.结果显示,在低温条件下,交换相互作用足够强的时候,系统给出的自旋过滤效率接近1. 相似文献
20.
Keldysh's nonequilibrium Green's function is applied to studying resonant magnetotunneling through a quantum dot. We propose a microscopic Anderson-impurity-like Hamiltonian in which two kinds of the on-site Coulomb interactions are introduced:the interaction of two electrons at the same Landau level with different spins, U1 and the interaction for the electrons between different Landau levels, U1. I-V curves are obtained under different magnetic fields in asymmetrical structures which can display both the energy quantization and singleelectron charging effect. The theoretical results are in good agreement with the experiments qualitatively. The linear-response conductance is also discussed. 相似文献