共查询到20条相似文献,搜索用时 31 毫秒
1.
YANG Xihua SUN Zhenrong LI Hua DING Liang’en WANG Zugeng 《Chinese Journal of Lasers》2001,10(2):123-126
1 Introduction Electromagneticallyinducedtransparency(EIT)hasattractedmuchattentionduetoitsextensiveapplications,suchasquantumnoisereduction[1] ,pulsematching[2 ,3] ,andenhancementofnonlinearmixing[4 ,5] .Inessence,EITisanatomiccoherenceinducedbyastrongcouplingl… 相似文献
2.
A. L. Gogyan N. V. Sahakyan Yu. P. Malakyan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2012,47(4):161-167
We propose a method of all-optical investigation of radiofrequency (RF) radiation based on the coherent effect of electromagnetically induced transparency (EIT). It is shown that if the atomic coherence is perturbed by an RF field, the shape of probe pulse propagating in a three-level ??-type atomic medium under EIT conditions is modified correspondingly to the temporal structure of the RF pulse. The effect is sensitive to the parameters of the pulse which enables measuring the intensity and the spectrum of the RF pulse. The method can be used for storage and lossless transfer of RF information over long distances using optical pulses. 相似文献
3.
三能级电磁感应透明中辐射场的量子统计特性 总被引:7,自引:4,他引:3
对Λ型三能级原子电磁感应透明(EIT)过程中辐射场的二阶相干度进行了研究。理论分析表明,在电磁感应透明系统中,由于原子的相干效应导致其上能级共振荧光场的二阶相干度将呈现单光子场的量子统计特性。并对其随耦合场强度和探测光失谐的变化进行了详细的分析和讨论,结果发现:在|Ω|〉(Γ2+Γ3)/2情况下.采用较弱的耦合光功率(由托比频率Ω表征)及较大的探测光失谐,在较长时间延迟范围内,二阶相十度保持小于1,更利于实现非经典场的量子统计行为;相反,在|Ω|≤(Γ2+Γ3)/2情况下,探测光的失谐量越小,越利于获得二阶相干度小于1的量子统计光场。南此可见选取合适的参量可优化电磁感应透明过程中单光子场的量子统计特性。 相似文献
4.
Light absorption and slowing down when traveling in a medium of four-level atoms with a doublet of close-lying upper levels is studied in conditions of electromagnetically induced transparency (EIT). It is shown that the presence of the second upper level leads to an increase in the absorption of the probe pulse. However, a control-pulse-detuning range exists between the doublet levels where light decelerates considerably more than in the case of ideal EIT. 相似文献
5.
Coherent manipulation of stored images is performed at low light levels based on enhanced cross-Kerr nonlinearity in a four-level N-type electromagnetically induced transparency (EIT) system. Using intensity masks in the signal pulse, quadratic phase shifts with low nonlinear absorption can be efficiently imprinted on the Fraunhofer diffraction patterns already stored in the EIT system. Fast-Fourier-transform-based numerical simulations clearly demonstrate that the far-field images of the retrieved probe light can be flexibly modulated by applying different signal fields. Our studies could help advance the goals of nonlinear all-optical processing for spatial information coherently stored in EIT systems. 相似文献
6.
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
7.
We analyze the energy storage process of light propagating with slow group velocity in a sample where electromagnetically induced transparency (EIT) is created by a strong coupling field. We compare the formation of slow light in EIT and in self-induced transparency (SIT). For SIT, soliton-like propagation of light with essentially reduced group velocity takes place because of the temporary storage of an appreciable part of the pulse energy in the atoms. For EIT, no energy of the probe is stored in the atoms. This energy is transformed to the coupling field and leaves the sample with phase velocity c without absorption. Slow light is formed by a low frequency coherence induced at the input by the probe and coupling fields in a two-quantum excitation process. This coherence propagates as a “spin wave” with small group velocity, and at a large distance from the input, the coherence rules the process of the energy transformation from the coupling field to the probe, reproducing exactly the temporal profile of the probe at the input. 相似文献
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9.
KUANGLe-Man ZENGAi-Hua KUANGZhen-Hua 《理论物理通讯》2004,42(3):407-412
We develop a full quantum theory of transient-state electromagnetically induced transparency (EIT) in the vapor of three-level A-type atoms interacting with probe and coupling lasers. As applications of the full quantum theory, we show that transient-state EIT medium exhibits normal dispersion and find that group velocities of both coupling and probe lasers are greatly reduced. It is shown that the group velocity of the probe laser in the transient-state EIT case is equal to that in the adiabatic EIT case and that the coupling laser group velocity in the transient-state EIT is generally less than that in the adiabatic EIT. 相似文献
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11.
报道了基于85RbD2线电磁诱导透明(EIT)的量子干涉现象,发现当一耦合光和探测光之间满足拉曼共振条件时出现电磁诱导透明现象,在某些条件下也观察到电磁诱导吸收(EIA).而当用一束耦合光和一束泵浦光共同作用于5S1/2,F=3→5P3/2,F′=3和5S1/2,F=3→5P3/2,F′=4能级上时,探测光的吸收谱表现出三峰结构,并且峰强弱与两耦合光之间的相对强度有关. 相似文献
12.
We develop a full quantum theory of transient-state electromagnetically induced transparency (EIT) in thevapor of three-level A-type atoms interacting with probe and coupling lasers. As applications of the full quantum theory,we show that transient-state EIT medium exhibits normal dispersion and find that group velocities of both coupling andprobe lasers are greatly reduced. It is shown that the group velocity of the probe laser in the transient-state EIT case isequal to that in the adiabatic EIT case and that the coupling laser group velocity in the transient-state EIT is generallyless than that in the adiabatic EIT. 相似文献
13.
Monte Carlo simulations of electromagnetically induced transparency in a square lattice of Rydberg atoms 下载免费PDF全文
《中国物理 B》2021,30(7):74206-074206
We study the steady optical response of a square lattice in which all trapped atoms are driven by a probe and a coupling fields into the ladder configuration of electromagnetically induced transparency(EIT). It turns out to be a manybody problem in the presence of van der Waals(vd W) interaction among atoms in the upmost Rydberg state, so Monte Carlo(MC) calculation based on density matrix equations have been done after introducing a sufficiently large cut-off radius. It is found that the absorption and dispersion of EIT spectra depends critically on a few key parameters like lattice dimension, unitary vd W shift, probe Rabi frequency, and coupling detuning. Through modulating these parameters, it is viable to change symmetries of the absorption and dispersion spectra and control on demand depth and position of the transparency window. Our MC calculation is expected to be instructive in understanding many-body quantum coherence effects and in manipulating non-equilibrium quantum phenomena by utilizing vd W interactions of Rydberg atoms. 相似文献
14.
对在掺杂稀土离子晶体中实现电磁感应光透明进行了实验研究。首先,以Er3+∶YAG晶体为样品,用旋转波近似下的密度矩阵方程理论计算了探测场的吸收特性随Er3+离子浓度的变化规律,结果表明:在探测场失谐Δp=0时,形成了一个对于探测光透明的窗口,从而在理论上论证了在掺杂稀土离子晶体中实现电磁感应光透明效应的可行性。设计了一个以Pr3+∶Y2SiO5晶体为样品的实验激发方案,吸收光谱显示,当温度为6 K时其在共振吸收峰处可形成一个完全透明的窗口,实现了在掺杂离子晶体中的电磁感应光透明。实验还分析了工作温度、耦合场失谐对探测光透过率的影响,结果显示:当样品温度上升到15 K时,透明窗口消失;耦合场的失谐量越大,透射率越小。 相似文献
15.
M. M. Hossain S. Mitra S. Chakrabarti D. Bhattacharyya B. Ray P. N. Ghosh 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,53(2):141-146
We report the experimental observation of electromagnetically induced transparency (EIT) in a Doppler broadened rubidium vapour
at room temperature for different probe intensities at a fixed pump intensity in a five-level Λ-type system formed by the
D2 transition of 85Rb. For a constant pump intensity, we find that the EIT width and height change with the variation of probe intensity. We
observe a nonlinear variation of the height of the EIT peak and a linear variation of the width (FWHM) of the EIT signal with
probe intensity. In the Doppler broadened multilevel system, we also observe the velocity selective dips along with the EIT
signal. A numerical simulation of the probe response signal based on density matrix representation in a five-level system
is carried out to reproduce the experimentally observed spectra. 相似文献
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17.
We report an experimental observation of slow light propagation in cold Rb atoms exhibiting cavity electromagnetically induced transparency (EIT). The steep slope of the atomic dispersion manifested by EIT reduces the light group velocity. The cavity filtering and feedback further contribute to the slowdown and delay of the light pulse propagation. A combination of the cavity and the EIT atomic system significantly improves the performance of the slow light propagation. A propagation time delay of approximately 200 ns was observed in the cavity and Rb EIT system, which is approximately 70 times greater than the time delay calculated for the light pulse propagation through the same Rb EIT system without the cavity. 相似文献
18.
Yu Qian Ye Jian Qi Shen Yi Jin 《Applied Physics A: Materials Science & Processing》2008,93(2):505-509
The band structures and equifrequency contours of one-dimensional photonic crystals (PCs), which consist of an electromagnetically
induced transparency (EIT) medium and a common dielectric medium, can be dramatically changed by tuning the coupling field
intensity (or coupling Rabi frequency, CRF) of the EIT medium. It is found that for a probe light at a fixed frequency, either
positive or negative refraction in the EIT PC can be realized with a proper CRF. The behavior of a Gaussian beam (probe light)
obliquely incident on such an EIT PC slab is simulated numerically. The probe light beam transmitted from the slab can be
shifted transversely in a large range, and negative refraction enhances this effect. The present scenario can be applied in
some areas such as quantum optical and photonic device designs. 相似文献
19.
准Λ型四能级原子系统在弱场中的增益及电磁感应透明 总被引:1,自引:1,他引:0
利用数值模拟的方法讨论了稳态下准型四能级原子与两光场相互作用系统对探测场的增益以及与粒子数布居规律之间的关系。结果表明即使在场较弱的情况下,随着探测场和它所对应能级间跃迁频率失谐量的变化,系统在所有拉比频率相位为零时对探测光总会同时呈现三个增益峰和两个固定的产生电磁感应透明(EIT)现象的位置,并且当系统呈现电磁感应透明的同时,探测场所对应的高能级粒子数为零;而拉比频率相位的变化则会导致系统对探测光既有吸收也有增益,并且也呈现电磁感应透明现象,但仅仅相位的变化并不影响高能级的粒子数分布。值得注意的是该结果均在精确求解下所得。 相似文献
20.
We have studied electromagnetically induced transparency (EIT) spectra in a frequency span as wide as 300 MHz. This tunability of EIT spectra provides an opportunity to utilize the sub-natural spectra in measuring unknown laser frequency very accurately. EIT is observed when control and probe laser frequency detunings are equal. This correlation has been used to identify and measure unknown probe frequency with a very high degree of accuracy, subject to the condition that control laser frequency is known. 相似文献