共查询到20条相似文献,搜索用时 15 毫秒
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Off-Axis and Multi Optical Bottles from the Ring Airy Gaussian Vortex Beam with the Astigmatic Phase
You Wu Zejia Lin Chuangjie Xu Xinming Fu Kaihui Chen Huixin Qiu Dongmei Deng 《Annalen der Physik》2020,532(7):2000188
A new type of off-axis and multi optical bottle (OB) from an astigmatic-phase ring Airy Gaussian vortex beam (APRAGVB) propagating in free space is derived numerically. By choosing appropriate parameters, different sizes and amounts of OBs can be obtained. More importantly, when the APRAGVB has the multi optical vortices at different locations, one can generate off-axis, multi, and complex OBs. It is believed that the results can diversify optical tweezers applications for multi microparticle manipulation. 相似文献
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LI Jia-Hua WANG Wen-Yi 《理论物理通讯》2004,42(7)
In this paper, we analyze and discuss the absorption properties of the probe beam in a four-level atomic system with a nearly hyper-fine doublet structure of two higher-lying excited levels based on electromagnetically induced transparency (EIT) for the two cases of transient process and steady-state process. The main gain of this work is to investigate theoretically the influence of the nearly hyper-fine levels on the probe absorption. For the transient process,using the numerical calculations by a simple Mathematica code we find that the magnitude of the probe absorption at the line center is small compared to the typical three-level atomic system in the context of electromagnetically induced transparency. For the case of the steady state, our results show that the probe absorption can be completely eliminated at the line center of the probe transition just as the usual three-level EIT scheme. 相似文献
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Two-photon resonant nondegenerate four-wave mixing (NFWM) with the
addition of a coupling field in Ba atomic vapour has been studied. We
find that coherence of the atomic level transitions leads to
suppression of the NFWM signal, giving rise to a dip with a linewidth
that is linearly proportional to the intensity of the coupling field. 相似文献
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The propagation dynamics of the Airy Gaussian vortex beams in uniaxial crystals orthogonal to the optical axis has been investigated analytically and numerically. The propagation expression of the beams has been obtained. The propagation features of the Airy Gaussian vortex beams are shown with changes of the distribution factor and the ratio of the extraordinary refractive index to the ordinary refractive index. The correlations between the ratio and the maximum intensity value during the propagation, and its appearing distance have been investigated. 相似文献
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LIJia-Hua WANGWen-Yi 《理论物理通讯》2004,42(1):113-116
In this paper, we analyze and discuss the absorption properties of the probe beam in a four-level atomic system with a nearly hyper-fine doublet structure of two higher-lying excited levels based on electromagnetieally induced transparency (EIT) for the two cases of transient process and steady-state process. The main gain of this work is to investigate theoretically the influence of the nearly hyper-fine levels on the probe absorption. For the transient process, using the numerical calculations by a simple Mathematica code we find that the magnitude of the probe absorption at the line center is small compared to the typical three-level atomic system in the context of electromagnetieally induced transparency. For the case of the steady state, our results show that the probe absorption can be completely eliminated at the line center of the probe transition just as the usual three-level EIT scheme. 相似文献
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Quan Li Chao Wu Xuan Liu Song Zhao Zhihui Zhang Xiaobing Shang Zeyong Wei Hongqiang Li 《Annalen der Physik》2019,531(12)
A geometric phase model for electromagnetic radiating elements is proposed. By rotation of the radiating element, a frequency‐independent geometric phase occurs for circularly polarized components of radiation field along every direction in far field. In addition, the geometric phase is equal to the rotation angle for a circularly polarized source, which enables phase modulation ranging from 0 to 2π. In contrast, the Pancharatnam–Berry phase for circular polarization conversion components brought by optical element rotation is twice the rotation angle and is applicable only for the scattering waves propagating along the rotation axis. As a proof of principle, an antenna array is designed and fabricated in microwave regime to verify the phase modulation approach. Both the calculated and measured results verify that three different orbital angular momentum modes are generated simultaneously at 8.5 GHz and 11.5 GHz. 相似文献
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We propose an optical Airy transform in this paper, and obtain the analytical expressions for the Airy transform of fundamental Gaussian beams and finite energy Airy beams. The setup for performing the optical Airy transform is presented. The Airy transform for Gaussian beams and finite energy Airy beams are theoretically calculated and analyzed. Our results show that the Airy beam can be conveniently generated and controlled through the optical Airy transform of the Gaussian beam. The optical Airy transform also can be used to directly modulate the beam parameters of the incident Airy beam, and it can transform the incident Airy beam into the Gaussian beam. 相似文献
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Kaiyun Zhan Ruiyun Jiao Jing Wang Wenqian Zhang Zhendong Yang Bing Liu 《Annalen der Physik》2020,532(3):1900546
The self-imaging effect based on Airy beams with quadratic phase modulation (QPM) in 1 + 1 and 2 + 1 dimensions is studied both numerically and analytically. It is demonstrated that, in spite of spatial spectral shape being kept invariant, both the intensity pattern and the accelerating trajectory of this self-imaging effect depend considerably on the QPM. When the QPM parameter is negative, the self-imaging accelerating wave exhibits deceleration and then acceleration, and the self-imaging scope can be expanded. In the opposite case, the self-imaging extent would be narrowed and the self-imaging accelerating wave will only accelerate during propagation. Numerical simulations agree with the theoretical results very well. This study shows the possibility of controlling the self-imaging effect based on 1D and circular Airy beams, by purposely choosing appropriate QPM parameters. 相似文献
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Electromagnetically induced transparency based six-wave mixing in a Doppler-broadened folded four-level system 下载免费PDF全文
We study phase-conjugate six-wave mixing spectroscopy based on electromagnetically-induced-transparency in a Doppler-broadened folded four-level system.It is found that the six-wave mixing spectrum can be either Doppler-free or very broad,depending on whether the interference between the polarisations of atoms with different velocities is constructive or destructive.To obtain the Doppler-free six-wave mixing spectrum in the folded four-level system,the conditions are more stringent in comparison with those in the cascade and N-type four-level systems.This polarisation interference can be controlled in the presence of a strong coupling field. 相似文献
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If a coherent perturbation field is used to couple the excited level of the coupling transition in the five-level K-type atom with another higher excited level, the two-photon electromagnetically induced transparency can be locally modulated by altering the parameters of the additional perturbation field. With different detunings of the coherent perturbation field, the absorption peak or transparency window with sharp and high-contrast speetrM feature can be generated in the two-photon absorption spectrum. The physical interpretation of these phenomena is given in terms of the dressed states. 相似文献
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In this paper, based on the constructive interference of plasmonic dipolar and quadrupolar modes, a classical analogue of electromagnetically induced absorption (EIA) is demonstrated theoretically in a stacked metamaterial consisting of a short metal strip (which acts as a bright resonator) and a long metal strip (acting as a dark resonator), which has been reported to support the electromagnetically induced transparency (EIT) effect. The transition from EIA to EIT can be clearly observed in the absorbance spectra via varying the vertical spacing between two resonant oscillators. With the help of the coupled two-oscillator model, the phase shift between the bright and dark resonance modes is calculated by fitting the simulated absorbance spectra, which reveals the physical mechanisms behind constructive and destructive interference effects in EIT/EIA metamaterials. 相似文献
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电磁诱导透明是在介质中由不同的入射光诱导产生的量子干涉效应。它以其独特的物理现象,在量子通信和非线性光学应用中具有重要的地位。近年来,人工超材料发展十分迅速,并成为等离子体学领域的一个研究热点。超材料可以很好地调控其物理结构和特性,而且降低了对电磁诱导透明实验条件的要求,模拟出类似于电磁诱导透明的现象即等离激元诱导透明。本文介绍等离激元诱导透明的工作原理,总结实现等离激元诱导透明的几种结构,以及等离激元诱导透明的研究现状,为微型传感器的应用以及等离激元诱导透明结构的设计提供依据。 相似文献
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We propose an efficient scheme for optimizing the optical memory of a sequence of signal light pulses in a system of ultracold atoms in Λ configuration. The memory procedure consists of write-in, storage, and retrieval phases. By applying a weak microwave field in the storage stage, additional phase-dependent terms are included, and the contrast of the output signal pulses can be dynamically controlled (enhanced or suppressed) through manipulating the relative phase φ between optical and microwave fields. Our numerical analysis shows that the contrast is enhanced to the most extent when φ=1.5π. In addition, the contrast is in proportion to the Rabi frequency of the microwave field with a certain relative phase. 相似文献
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Propagation dynamics of a two-dimensional Airy Gaussian beam and Airy Gaussian vortex beam are investigated numerically in local and nonlocal nonlinear media. The self-healing and collapse of the beam crucially depend on the distribution factor b and the topological charge m. With the aid of nonlocality, a stable Airy Gaussian beam and an Airy Gaussian vortex beam with larger amplitude can be obtained, which always collapse in local nonlinear media. When the distribution factor b is large enough, the Airy Gaussian vortex beam will transfer into quasi-vortex solitons in nonlocal nonlinear media. 相似文献
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