共查询到20条相似文献,搜索用时 15 毫秒
1.
We study electromagnetically-induced transparency (EIT) of a probe field in a Doppler- broadened five-level K-type atomic system driven by three strong laser (coupling) fields. Effect of wave-vector mismatch occurring when the coupling field frequency is higher than that of the probe field frequency (λ c < λ p) are considered. Under the influence of the coherent coupling fields, the steady-state linear susceptibility of the probe laser shows that the system can have single or double or triple EIT windows depending on the amplitude and detuning of the coupling fields. 相似文献
2.
Electromagnetically induced transparency of single Λ-type three-level atom in high-finesse optical cavity 下载免费PDF全文
We study the features of the electromagnetically induced transparency (EIT) in a single Λ-type three-level atom placed in a high finesse cavity under the action of a coupling laser and a probe laser. Our calculations show that three transparency windows appear when the pump strength is big enough. It can be explained by the residual pump in the cavity resulting mostly in the energy splitting. Level |3〉is split into four slightly different energy levels. An interference takes place between excitation pathways. Furthermore, it is also shown that the frequencies of the EIT windows can be tuned by changing the coupling field detuning Δ2 and the reflection profile is very sensitive to the cavity field detuning Δc. 相似文献
3.
4.
Electromagnetically induced transparency and quadripartite macroscopic entanglement generated in a ring cavity 下载免费PDF全文
We propose a feasible scheme to generate electromagnetically induced transparency(EIT) and quadripartite macroscopic entanglement in an optomechanical system with one fixed mirror and three movable perfectly reflecting mirrors.We explore the EIT phenomena in this optomechanical system.Results show the appearance of EIT dips in the output field.Moreover,we demonstrate how steady-state quadripartite entanglement can be generated via radiation pressure.We also quantify the bipartite entanglement in each field-mirror subsystem and in the mirror-mirror subsystem.Findings show that a high intensity of entanglement between two subsystems can be achieved. 相似文献
5.
The effect of electromagnetically induced transparency (EIT) in a Λ-system formed by rubidium atoms contained in thin (10–60
μm) and extremely thin (0.3–5 μm) cells was studied experimentally. It was found that parameters of the EIT resonance degrade
slowly in the case where the frequency of the coupling laser is in resonance with the D
2 transition of rubidium, which enabled the registration of the EIT resonance in a record thin cell with a thickness of L = 390 nm. The specific features of EIT in extremely thin cells reveal themselves when the coupling laser has a frequency
detuning Δ from the atomic transition. In this case, the width of the EIT resonance rapidly increases upon an increase in
Δ at fixed L (an opposite effect takes place in centimeter-scale cells). It is shown that the width of the EIT resonance is inversely
proportional to L in the case of fixed large detuning Δ. The nearly tenfold broadening of the EIT resonance for large values of detuning Δ
is caused by the influence of atomic collisions with cell windows on dephasing rate of coherence. The expressions that allow
the estimation of the EIT-resonance width for various values of detuning Δ and small values of thickness L are found. 相似文献
6.
A nondegenerate four-level N-type scheme was experimentally implemented to observe electromagnetically induced transparency (EIT) at the 87Rb D 2 line. Radiations of two independent external-cavity semiconductor lasers were used in the experiment, the current of one of them being modulated at a frequency equal to the hyperfine-splitting frequency of the excited 5P 3/2 level. In this case, apart from the main EIT dip corresponding to the two-photon Raman resonance in a three-level L-scheme, additional dips detuned from the main dip by a frequency equal to the frequency of the HF generator were observed in the absorption spectrum. These dips were due to an increase in the medium transparency at frequencies corresponding to the three-photon Raman resonances in four-level N-type schemes. The resonance shapes are analyzed as functions of generator frequency and magnetic field. 相似文献
7.
M. M. Hossain S. Mitra B. Ray P. N. Ghosh 《Applied physics. B, Lasers and optics》2011,102(1):117-122
We report the experimental observations of double EIT and enhanced EIT signal in a combination of Λ- and V-type multi-level
system of the D2 transition of 85Rb atoms interacting with three laser fields. The EIT formation under a Λ-type and V-type systems is also observed separately.
It is found that the EIT width in a V-type system becomes narrower than the Λ-type system. Also the effect of frequency detuning
of the control laser on the probe absorption profile is studied in presence of Λ- and V-type EIT systems. 相似文献
8.
Electromagnetically induced self-imaging 总被引:1,自引:0,他引:1
We study the self-imaging and image-transforming properties of a probe field in a cold atomic medium with electromagnetically induced transparency (EIT). Due to the similarities between the gradient-index medium and the inhomogeneous index distribution of an EIT medium under the conditions of a negative probe detuning and a Gaussian control field, we find based on analytical investigations that there exists a kind of electromagnetically induced self-imaging phenomenon in cold atomic media. Numerical simulations clearly show that electromagnetically induced self-imaging is observable and controllable. 相似文献
9.
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
10.
I. A. Semerikov I. V. Zalivako A. S. Borisenko K. Y. Khabarova N. N. Kolachevsky 《Journal of Russian Laser Research》2018,39(6):568-574
We propose a method for EIT ground state cooling of 171Yb+ ion, which involves three light fields with detuning on a MHz scale. The steady-state mean vibrational quantum number is calculated to be less than 0.005. Efficient cooling is achievable in a motional-mode frequency range of 2π · (1.5 ± 0.5 MHz). 相似文献
11.
Absorption properties of a driven Doppler—broadened ladder system with hyperfine structure 下载免费PDF全文
We have studied the absorption spectrum of a Doppler-broadened ladder system,where the highest level is coupled into two middle hyperfine sublevels by a strong coherent field.We find that,when the system is considered as homogeneous,either two or three spectral components are observed,depending on the detuning of the coherent field.but when the velocity distribution of atoms is considered,we can always observe one electromagnetically induced transparency (EIT) window with high dispersion.So the atomic hyperfine structure cannot be an impediment for obtaining EIT. 相似文献
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13.
Nonlinear cascade-configuration multi-wave mixing scheme based on electromagnetically induced transparency 下载免费PDF全文
A nonlinear optical cascade-configuration multi-wave mixing (CCMWM) scheme is presented and analysed for the generation of coherent light in a six-level atomic system in the context of electromagnetically induced transparency (EIT). A detailed semi-classical study of the propagation of the generated mixing and probe fields is demonstrated. We show by numerical simulations that EIT is capable of suppressing linear and nonlinear photon absorption. The analytical dependence of the generated mixing field on the probe field and the respective detuning is also predicted. Such a nonlinear optical process can be used for generating coherent short-wavelength radiation. 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.
利用数值计算结果,讨论了在Y型四能级原子系统中Doppler展宽对与真空诱导相干性(VIC) 相关的探测场吸收性质的影响.研究结果表明: 当无Doppler展宽时,只有不存在VIC时才可能产生电磁感应透明(EIT)现象; VIC将导致探测场吸收的明显改变和增益产生;在VIC存在和不存在两种情况中,吸收曲线都具有关于探测场失谐对称的双峰结构. 当有Doppler展宽时,在VIC存在和不存在两种情况中都能产生EIT现象; VIC仍将导致探测场吸收的明显改变和增益产生;不管是否存在VIC,探测场吸收都具有以下特征:吸收曲线不再具有关于探测场失谐的对称性且随Doppler展宽宽度(D)值的增大而逐渐从双峰结构变为单峰结构,探测场吸收不随D值的增大而单调增大或减小,在探测场和驱动场的传播方向相反时可获得比传播方向相同时更小的探测场吸收. 相似文献
16.
L. S. Cruz D. Felinto J.G. Aguirre Gómez M. Martinelli P. Valente A. Lezama P. Nussenzveig 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(3):531-539
High degrees of intensity correlation between two independent lasers were
observed after propagation through a rubidium vapor cell in which they generate
Electromagnetically Induced Transparency (EIT). As the optical field intensities are
increased, the correlation changes sign (becoming anti-correlation). The experiment was
performed in a room temperature rubidium cell, using two diode lasers tuned to the
85Rb D2 line (λ= 780 nm). The cross-correlation spectral function for the
pump and probe fields is numerically obtained by modeling the temporal dynamics of both
field phases as diffusing processes. We explored the dependence of the atomic response on
the atom-field Rabi frequencies, optical detuning and Doppler width. The results show
that resonant phase-noise to amplitude-noise conversion is at the origin of the observed
signal and the change in sign for the correlation coefficient can be explained as a
consequence of the competition between EIT and Raman resonance processes. 相似文献
17.
In this paper, the electromagnetic characteristics of quasi-Λ-four-level atomic system influenced by electromagnetically induced transparency (EIT) effect with double windows are investigated theoretically. It is shown that the permittivity can get two negative extreme values in transparent window extents and the permeability can realize negative value. Consequently, the atomic system can obtain the negative refraction in discontinuous probe detuning frequency ranges. EIT effect with double transparent windows would extend the tuning frequency range of realizing left handedness in atomic system. Furthermore, due to the strong magnetic transition, the real part of the refractive index and the absorption of atomic system can obtain negative values in the same certain frequency band. Such left-handed quasi-Λ-four-level atomic system may become an active medium. 相似文献
18.
Pradip Laha B. Sudarsan S. Lakshmibala V. Balakrishnan 《International Journal of Theoretical Physics》2016,55(9):4044-4059
A Λ-type atom interacting with two radiation fields exhibits electromagnetically induced transparency and other nonclassical effects that appear in the entanglement dynamics of the atomic subsystem and in appropriate field observables. Both EIT and field-atom entanglement are important for quantum information processing. We investigate the roles played by specific initial field states, detuning parameters, field nonlinearities and intensity-dependent field-atom couplings on EIT and the entanglement between subsystems. Departure from coherence of the initial field states produces significant effects. We investigate these aspects in a model that exhibits the salient features of entangled tripartite systems. For initial photon-added coherent states, collapses and revivals of the atomic subsystem von Neumann entropy appear as the intensity parameter varies over a narrow range of values. These features could be useful in enabling entanglement. 相似文献
19.
在通常的Λ型三能级系统中,光学耦合场和探测场分别激发两个不同的光学跃迁,探测吸收谱呈现电磁诱导透明(EIT)特性.若将此系统拓展为光学-射频双光子耦合场和探测场共同作用下的准Λ型四能级系统,探测吸收谱呈现电磁诱导吸收(EIA)和EIT两种特性.通过求解系统的密度矩阵方程,分析了EIA和EIT的产生条件,并给出了相应的缀饰态解释.研究结果表明,在准Λ型四能级系统中,光学耦合场对EIA和EIT的形成起决定作用,共振时出现EIA,非共振时出现EIT,而且EIA和EIT的线宽随着光学耦合场拉比频率的增大而增加.
关键词:
电磁诱导透明
电磁诱导吸收
射频场
光学耦合场 相似文献
20.
We report experimental observations on the simultaneous electromagnetically induced transparency (EIT) effects for probe and trigger fields (double EIT) as well as the enhanced cross-phase modulation (XPM) between the two fields in a four-level tripod EIT system of the D1 line of 87Rb atoms. The XPM coefficients (larger than 2 x 10(-5) cm2/W) and the accompanying transmissions (higher than 60%) are measured at a slight detuning of the probe field from the exact EIT-resonance condition. The system and enhanced cross-Kerr nonlinearities presented here can be applied to quantum information processes. 相似文献