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简要介绍了量子相干和干涉效应的研究动态和一项最新理论研究进展.设计了一个存在Fano类型隧穿感应量子干涉的GaAs/A lxGa1-xAs非对称量子阱结构.在该量子阱中,可通过一束控制光抑制量子干涉,进而调制信号光的传播特性.这一现象可用来实现一个宽带超快全光开关. 相似文献
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Dynamical effects of the four-wave mixing enhancement induced by constructive quantum interference 下载免费PDF全文
In a four-level system of ultracold 87Rb atoms, through analytical and numerical calculations we propose an efficient scheme to achieve the enhanced four-wave mixing process and demonstrate its dynamical control by various parameters such as the travel distance z, probe detuning $\delta$ and the probe pulse width $\tau$. In particular, we find that the maximal intensity of the nonlinearly generated signal pulse can be about 80% of the initial input probe under the optimal condition. This greatly enhanced conversion efficiency occurs due to the constructive quantum interference between two different components of the generated signal pulse. 相似文献
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类型1 a_(n 1)=pa_n q例1 (2006福建(理))已知数列{a_n}满足a_1=1,a_(n 1)=2a_n 1(n∈N~*),求数列{a_n}的通项公式.解由已知a_(n 1)=2a_(n 1),两边同除以2~(n 1),得(a_(n 1))/(2~(n 1))=(a_n)/(2~n) 1/(2~(n 1)).变形得(a_(n 1))/(2~(n 1)) 1/(2~(n 1))=(a_n)/(2~n) 1/(2~n),∴数列{(a_n)/(2~n) 1/(2~n)}是常数列,即(a_n)/(2~n) 1/(2~n)=(a_1)/2 1/2,故所求数列通项为a_n=2~n-1.点拨形如a_(n 1)=pa_n q(p、q常数,p≠1,q≠0)的递推关系求通项,通常先两边同除以 相似文献
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We study a three-mode double-cavity optomechanical system in which an oscillating membrane of perfect reflection is inserted between two fixed mirrors of partial transmission. We find that electromagnetically induced transparency (EIT) can be realized and controlled in this optomechanical system by adjusting the relative intensity and the relative phase between left-hand and right-hand input (probe and coupling) fields. In particular, one perfect EIT window is seen to occur when the two probe fields are exactly out of phase and the EIT window's width is very sensitive to the relative intensity of two coupling fields. Our numerical findings may be extended to achieve optomechanical storage and switching schemes applicable in quantum information processing. 相似文献
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Controllable beating signal using stored light pulseControllable beating signal using stored light pulseControllable beating signal using stored light pulse 下载免费PDF全文
We experimentally study the controllable generation of a beating signal using stored light pulses based on electro- magnetically induced transparency (EIT) in a solid medium. The beating signal relies on an asymmetric procedure of light storage and retrieval. After storing the probe pulse into the spin coherence under the EIT condition, two-color control fields with opposite detunings instead of the initial control field are used to scatter the stored spin coherence. The controllable beating signal is generated due to alternative constructive and destructive interferences in the retrieved signal intensities. The beating of the two-color control fields is mapped into the beating of weak probe fields by using atomic spin coherence. This beating signal will be important in precise atomic spectroscopy and fast quantum limited measurements. 相似文献
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We experimentally study the controllable generation of a beating signal using stored light pulses based on electromagnetically induced transparency(EIT) in a solid medium. The beating signal relies on an asymmetric procedure of light storage and retrieval. After storing the probe pulse into the spin coherence under the EIT condition, two-color control fields with opposite detunings instead of the initial control field are used to scatter the stored spin coherence. The controllable beating signal is generated due to alternative constructive and destructive interferences in the retrieved signal intensities. The beating of the two-color control fields is mapped into the beating of weak probe fields by using atomic spin coherence. This beating signal will be important in precise atomic spectroscopy and fast quantum limited measurements. 相似文献
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Phase-dependent inversionless gain in a four-level atomic system with a closed interaction loop 下载免费PDF全文
A four-level atomic system with a closed interaction loop connected
by two coherent driving fields and a microwave field is
investigated. The results show that inversionless gain can be
achieved on a higher frequency transition outside the closed
interaction loop, and the gain behaviour can be modulated by the
phase of the closed loop as well as the amplitude of the microwave
field. The phase sensitivity property in such a scheme is similar to
that in an analogous configuration with spontaneously generated
coherence, but it is beyond the rigorous condition of
near-degenerate levels with non-orthogonal dipole moments.
Therefore this scheme is much more convenient in experimental
realization. 相似文献
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The probe gain with and without inversion in a four—level atomic model:light amplification at a short wavelength 下载免费PDF全文
We propose a new four-level atomic model for achieving light
amplification at a short wavelength, where direct incoherent
pumping into the top level is avoided by the advantage of
coherent pumping. In this model, the lower level of the probe
transition is an excited state but not the usual ground state.
By analytical as well as numerical calculations, we find that the
probe gain, either with or without population inversion, which depends
on the relation between spontaneous decay rates $\g_{42}$ and $\g_{21}$, can be achieved with proper parameters. We note that the Raman scattering
gain always plays an important role in achieving the probe amplification. 相似文献