共查询到20条相似文献,搜索用时 15 毫秒
1.
X. Y. Hao J. H. Li X. Y. Lü X. Yang 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,56(2):239-246
We investigate optical amplification and absorption properties under
a closed-loop double-Λ configuration in an asymmetric
semiconductor coupled-double-quantum-well (CDQW) nanostructure based
on interband transitions (IBTs). In the proposed CDQW scheme, the
amplification, absorption or zero-absorption (transparency) of the
probe field and the signal field can be realized with realistic
experimental parameters by appropriately adjusting the relative
phase, the two pump Rabi energies, the probe detuning, and the
Fano-interference strength, respectively. Such a semiconductor
system is much more practical than its atomic counterpart because of
its flexible design and the wide adjustable parameters. 相似文献
2.
Asadpour Seyyed Hossein Rahimpour Soleimani H 《中国物理 B》2014,(10):248-253
The effect of Er3+ ion concentration on transient and steady-state behavior in 45-nm Er3+ :YAG crystal is investigated. It is shown that by changing the signal field, the coherent field and the concentration of Er3+ ions in the crystal, the absorption, dispersion, and group index of the weak probe field can be adjusted. Also, it is found that the probe absorption occurs in the presence of population inversion and probe amplification is obtained in the absence of population inversion. 相似文献
3.
4.
LI Jia-Hua YANG Wen-Xing PENG Ju-Cun 《理论物理通讯》2004,42(9)
We discuss and analyze the absorption-amplification properties of a weak probe field in a typical four-level atomic system in the presence of an additional coherence term, the spontaneously generated coherence term. Theinfluences of the spontaneously generated coherence and a coherent pump field on the probe absorption (amplification)are investigated in detail. We show that the absorption of such a weak probe field can be dramatically enhanced dueto the presence of the spontaneously generated coherence. At the same time, the probe-absorption profile exhibitsthe double-peak structure and the probe-absorption peak gradually decreases as the pump intensity increases. On thecontrary, the amplification of such a weak probe field near the line center of the probe transition can be achieved byadjusting the coherent pump field intensity in the absence of the spontaneously generated coherence. 相似文献
5.
We discuss and analyze the absorption properties of a weak probe field in a typical four-level atomic system in the presence of a spontaneously generated coherence (SGC) term. The influences of the SGC and a coherent pump field on the probe absorption-amplification are investigated. The results show that the absorption of such a weak probe field can be dramatically enhanced due to the SGC effect. At the same time, the probe-absorption profile exhibits a two-peak structure and the probe-absorption peak gradually decreases as the pump intensity increases. On the contrary, the amplification of such a weak probe field near the line center of the probe transition can be achieved by adjusting the coherent pump field intensity in the absence of the SGC effect. 相似文献
6.
Ultrashort pulse counterintuitive sequencing of three level lambda scheme shows five fold enhancement of the amplification
without inversion on the probe transition. Introducing a short pulse weak probe field prior to the strong pump field results
in an enhanced dispersion and stronger amplification on the probe field. The presence of an incoherent pump populating the
upper level is crucial to the amplification. Parametric study of this effect is briefly presented. 相似文献
7.
Zhiping Wang Benli Yu Xuqiang Wu Zhigang Cao Jun Zhu Shenglai Zhen Jun Peng 《Optik》2012,123(14):1240-1244
We theoretically investigate the absorption–amplification response of the probe field in a four-level cold 87Rb atomic system. It is found that the incoherent pumping fields play very important roles in realizing the amplification of the probe field. The transmission property of the probe field is also studied. 相似文献
8.
We propose and analyze a new scheme to realize efficient weak-light amplification via phase control in a GaAs quantum well (QW) waveguide when driven coherently by two orthogonally polarized optical fields (a σ-polarized probe field and a π-polarized control field). It is shown that the amplification and absorption properties of the system are very sensitive to the relative phase between these driving fields. By choosing the relative phase appropriately, the enhanced amplification of the weak σ-polarized radiated field can be achieved in such a QW waveguide. We support our results by numerical calculation and analytical explanation. These theoretical investigations may find applications in devising the QW waveguide amplifier at room temperature. 相似文献
9.
A. I. Parkhomenko A. M. Shalagin 《Journal of Experimental and Theoretical Physics》2005,100(2):283-293
The spectrum of weak probe field absorption (amplification) by two-level atoms experiencing collisions with buffer gas atoms in a strong resonance laser field is studied theoretically. Analysis is carried out for systems with a weak Doppler broadening under relatively mild constraints on the strong field intensity for the general case of an arbitrary change in the phase of the radiation-induced dipole moment in elastic collisions of gas particles. It is shown that, in spite of uniform broadening of the absorption line, the probe field spectrum exhibits a clearly manifested anisotropy to mutual orientation of the wavevectors of strong and probe radiation. It is found that the width of resonances in the probe field spectrum under definite conditions (that can easily be created in experiments) is proportional to the diffusion coefficient for atoms interacting with radiation. This fact can form the basis of the spectroscopic method for measuring the transport frequencies of collisions between particles absorbing radiation and buffer particles. It is shown that phase memory effects in collisions strongly modify the probe field spectrum both qualitatively and quantitatively. Simple operative formulas proposed for the probe field spectrum are convenient for experimental data processing. 相似文献
10.
Phase-dependent double optomechanically induced transparency in a hybrid optomechanical cavity system with coherently mechanical driving
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《中国物理 B》2019,(7)
We propose a scheme that can generate tunable double optomechanically induced transparency in a hybrid optomechanical cavity system.In this system, the mechanical resonator of the optomechanical cavity is coupled with an additional mechanical resonator and the additional mechanical resonator can be driven by a weak external coherently mechanical driving field.We show that both the intensity and the phase of the external mechanical driving field can control the propagation of the probe field, including changing the transmission spectrum from double windows to a single-window.Our study also provides an effective way to generate intensity-controllable, narrow-bandwidth transmission spectra, with the probe field modulated from excessive opacity to remarkable amplification. 相似文献
11.
Chun Xiao Zhou Xue Mei Su 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2014,68(2):1-6
We propose and demonstrate a scheme to realize large negative refraction dispersion when a probe field is amplified by cooperation between a coherent field and an incoherent pump. The probe pulse can propagate either subluminally or superluminally in the left-handed amplification medium by modulating parameters of the coherent and incoherent fields. 相似文献
12.
M. H. Hovhannisyan 《Journal of Contemporary Physics (Armenian Academy of Sciences)》2014,49(3):103-109
Abilities of the method of accumulation of coherent unstable response of a medium for amplification of the rotated component of the probe wave’s polarization in the atomic medium of three-level atoms are studied. Probe wave is examined in frames of the perturbation theory and its frequency is considered near to one photon resonance from the ground to the first excited level. The intense monochromatic pump field connects two excited energy levels and propagates through the medium without a change. The broadening of spectral lines caused by the relaxation processes and the Doppler broadening are included into the calculations. It is shown that by multiple consistent instantaneous change of input probe field’s phase from 0 to π and back, it is possible to obtain, in the tail part of the rotated component of the probe field, a separate narrowed light pulse along with the increase in intensity by more than an order of magnitude with respect to the input field. 相似文献
13.
Amplification mechanism and effects of spontaneously generated coherence on the probe gain in a four-level system
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We investigate the amplification mechanism in a four-level system by both the density-matrix and quantum-jump approaches. We show that the asymmetry between three-photon stimulated emission and one-photon absorption process is responsible for the inversionless amplification of the probe field. We also investigate the effects of spontaneously generated coherence (SGC) on the probe gain, and find that due to the SGC, the probe gain can be greatly enhanced and can be modulated by changing the relative phase between the applied fields. 相似文献
14.
15.
The optical properties of weak probe light based on quantum coherence and interference in Landau-quantized graphene nanostructure driven by two coherent fields and incoherent pumping field is investigated. The linear dynamical properties of the graphene by means of density matrix method and perturbation theory are discussed. It is found that under certain condition and for appropriate choosing the parameters of the medium, the absorption, dispersion, group index of the weak probe light can be controlled. Moreover, it is shown that by means of incoherent pumping field the superluminal light propagation in the system is accompanied by amplification to make sure that the probe field is amplified as it passes through the system. Moreover, it is observed that the probe amplification can be obtained in the presence or absence of population inversion by properly choosing of system’s parameters. We hope that these results may have useful in the future quantum communicational system and networks. 相似文献
16.
One- and two-photon absorption-amplification response in a four-level atomic system with vacuum-induced coherence
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This paper theoretically studies the effects of the vacuum-induced coherence
on one- and two-photon absorption in a four-level atomic medium.
It finds that the one- and two-photon absorption and amplification
properties are quite sensitive to the vacuum-induced coherence. It
is also shown that the one- and two-photon absorption spectra can
be dramatically affected by modulating the relative phase of the
applied fields. With the proper choice of the relative phase, the
amplification without inversion for the probe field can be
realized. 相似文献
17.
The coherent superposition of two-atomic levels induced by coherent population trapping is employed in the two-level system, the standard three-level Λ type scheme and the four-level N-type systems and a weak probe pulse scans across the system. A theoretical analysis about the response of medium to the probe field is given. It is shown that under different initial conditions, the coherent superposition of the dark state exhibits abundant optical phenomena response to the probe field. It can change the absorption or gain and the dispersion relationship in the medium experienced by the probe. In the embedded three-level scheme, the probe experiences a crossover from absorption to transparent and then to amplification. Consequently the group velocity of the probe pulse can be controlled to propagate either as a subluminal, a standard, a superluminal or even a negative speed. In the embedded four-level N-type system, it can give an enhancement to the Giant Kerr effect and overcome the limitation of two-photon absorption, then make the nonlinear properties of the medium richer than the traditional N-type scheme. 相似文献
18.
《中国物理 B》2015,(5)
We theoretically investigate the analog of electromagnetically induced absorption and parametric amplification in a hybrid opto-electromechanical system consisting of an optical cavity and a microwave cavity coupled to a common mechanical resonator. When the two cavity modes are driven by two pump fields, a weak probe beam is applied to the optical cavity to monitor the optical response of the hybrid system, which can be effectively controlled by adjusting the frequency and power of the two pump fields. We find that the analog of electromagnetically induced absorption and parametric amplification can appear in the probe transmission spectrum when one cavity is pumped on its red sideband and another is pumped on its blue sideband. These phenomena can find potential applications in optical switching and signal amplification in the quantum information process. 相似文献
19.
针对采用TEM小室或GTEM室校准测试时从输入端获取信号的需求,设计了一种同轴型脉冲电压探头;该探头为微分型输出,采用数值积分可获得脉冲电压波形;其灵敏度系数可调。仿真分析了不同结构探针对探头内部电场峰值分布及对端口特性阻抗的影响,对采用尖针形探针的同轴脉冲探头进行了实验验证,得到了其频域响应曲线和灵敏度系数,分析了灵敏度系数随探针到内导体中心距离变化的规律。仿真和实验结果表明,同轴脉冲探头内嵌的探针采用尖针形时,对端口特性阻抗的影响及内部电磁场的扰动都很小,可满足ns级瞬变脉冲测试校准需要。 相似文献
20.
M. Lintz J. Guéna M. -A. Bouchiat 《The European Physical Journal A - Hadrons and Nuclei》2007,32(4):525-529
We present the atomic parity violation measurements made in Cs vapour using a pump-probe scheme. After pulsed excitation of
the 6S -7S forbidden transition in the presence of a longitudinal electric field, a laser beam resonant with one of the 7S -6P transitions stimulates the 7S atom emission for a duration of 20ns. The polarisation of the amplified probe beam is analysed. A seven-fold signature allows
discrimination of the parity-violating linear dichroism, and real-time calibration by a similar, known, parity-conserving
linear dichroism. The zero-field linear dichroism signal due to the magnetic dipole transition moment is observed for the
first time, and used for in situ determination of the electric field. The result, ImE
1
pv = (- 808±21)×10-14
ea
0 , is in perfect agreement with the corresponding, more precise measurement obtained by the Boulder group. A transverse field
configuration with large probe amplification could bring atomic parity violation measurements to the 0.1% accuracy level. 相似文献