如何直接验证椭圆偏振光

对物理实验教材中有关椭圆偏振光实验不能直接验证椭圆偏振光存在的原因进行了分析,提出了可直接验证椭圆偏振光的数据处理方法     

Decoding the electron dynamics in high-order harmonic generation from asymmetric molecular ions in elliptically polarized laser fields

The high-order harmonic generation from an asymmetric molecular ion is theoretically investigated based on the Born-Oppenheimer model with two-dimensional electron dynamics. It is shown that the harmonic intensity changes periodically in elliptically polarized laser fields. The periodical character is ellipticity-dependent. By establishing the physical image, the periodicity of the harmonic intensity can be ascribed to the contributions of the ground state and the excited state. Furthermore, the electron dynamics from different electronic states can be selected via combining the elliptically polarized laser field with a static electric field. The harmonics dominated either by ground state or excited state are emitted once in an optical cycle in the combined laser field.     

Multiple scattering of elliptically polarized light in two-dimensional medium with large inhomogeneities

For elliptically polarized light incident on a two-dimensional medium with large inhomogeneities, the Stokes parameters of scattered waves are calculated. Multiple scattering is assumed to be sharply anisotropic. The degree of polarization of scattered radiation is shown to be a nonmonotonic function of depth when the incident wave is circularly polarized or its polarization vector is not parallel to the symmetry axis of the inhomogeneities.     

Control of Spontaneous Emission via a Single Elliptically Polarized Light in a Five-Level Atomic System

We investigate the features of the spontaneous emission spectra in a cold five-level atomic system coupled by a single elliptically polarized control field. We use wave function approach to derive the explicit and analytical expressions of atomic spontaneous emission spectra. It is shown that some interesting phenomena such as spectralline enhancement, spectral-line suppression, spectral-line narrowing, spectral-line splitting and dark fluorescence can be observed in the spectra by appropriately modulating the phase difference between the right-hand circularly (LHC) and left-hand circularly (RHC) polarized components of the elliptically polarized control field and the intensity of external magnetic field. The number of emission peaks, the positions of fluorescence-quenching points can be also controlled. Furthermore, we propose an ultracold 87Rb atomic system for experimental observation. These investigations may find applications in high-precision spectroscopy.     

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采用洛伦兹变换推导出左旋椭圆偏振强激光在磁化等离子体中的非线性色散关系,根据Karpman方法推导出激光场包络的非线性控制方程,分析了在磁化等离子体中左旋椭圆偏振激光的调制不稳定性,得到了调制不稳定的时间增长率。分析结果表明,磁化等离子体中自调制不稳定的极大增长率较非磁化情况明显减小,且在激光等离子体临界面附近处调制不稳定性的时间增长率显著增大。     

强激光在磁化等离子体中的调制不稳定性

采用洛伦兹变换推导出左旋椭圆偏振强激光在磁化等离子体中的非线性色散关系,根据Karpman方法推导出激光场包络的非线性控制方程,分析了在磁化等离子体中左旋椭圆偏振激光的调制不稳定性,得到了调制不稳定的时间增长率。分析结果表明,磁化等离子体中自调制不稳定的极大增长率较非磁化情况明显减小,且在激光等离子体临界面附近处调制不稳定性的时间增长率显著增大。     

Plasma Induced Wiggler Magnetic Field in a Cavity: II-FDTD Method for a Switched Lossy Plasma

The transformation of an elliptically polarized standing source wave in a cavity by a lossy plasma created with arbitrary space and time profiles is numerically computed using the Finite-Difference Time-Domain (FDTD) method. The FDTD equations derived are shown to be very robust and results are presented for several practical scenarios.     

Extracting the phase distribution of the electron wave packet ionized by an elliptically polarized laser pulse

We use an interferometic scheme to extract the phase distribution of the electron wave packet from above-threshold ionization in elliptically polarized laser fields. In this scheme, an electron wave packet released from a circularly polarized laser pulse acts as a reference wave and interferes with the electron wave packet ionized by a time-delayed counter-rotating elliptically polarized laser field. The generated vortex-shaped interference pattern in the photoelectron momentum distribution enables us to extract the phase distribution of the electron wave packet in the elliptically polarized laser pulse with high precision. By artificially screening the ionic potential at different ranges when solving the time-dependent Schördinger equation, we find that the angle-dependent phase distribution of the electron wave packet in the elliptically polarized laser field shows an obvious angular shift as compared to the strong-field approximation, whose value is the same as the attoclock shift. We also show that the amplitude of the angle-dependent phase distribution is sensitive to the ellipticity of the laser pulse, providing an alternative way to precisely calibrate the laser ellipticity in the attoclock measurement.     

Change in polarization of a weak signal induced by the optical pumping of atoms at an adjacent transition

A change in polarization of a weak wave under optical pumping of atoms at an adjacent atomic transition is studied. It is shown that an elliptically polarized probe signal undergoes substantial polarization changes in the field of a circularly polarized pump wave. For the probe wave component with the same circular polarization as that of a strong signal, the medium becomes transparent.     

Polarization singularity democracy: WYSIWYG

The canonical point singularity of elliptically polarized light is a C point, an isolated point of circular polarization surrounded by a field of polarization ellipses. The defining singular property of a C point is that the surrounding ellipses rotate about the point. It is shown that this rotation is seen only for a particular line of sight (LOS) and, conversely, that there exists a unique LOS for every ellipse along which the ellipse is seen as a singularity. It is also shown that changes in LOS can turn singularities into stationary points and vice versa. The democratic behavior of polarization singularities and stationary points is a consequence of the fundamental "what you see is what you get" property of ellipse fields. Simple experiments are proposed for observing this unusual property of elliptically polarized light.     

Polarization manipulated solid-state lasers with crystalline-orientations

The polarization states of 〈111〉-cut Yb:YAG crystal microchip lasers were investigated by pumped with the elliptically polarized pump beam from fiber-coupled laser-diode. The manipulated polarized lasers were achieved in laser-diode pumped Yb:YAG microchip laser by controlling the crystalline-orientations in 〈111〉-growth Yb:YAG crystal. Generally elliptically polarized lasers were obtained in laser-diode pumped Yb:YAG microchip lasers. However, crystalline-orientation manipulated linearly polarized laser was obtained when six different sites with different crystalline orientations were set to parallel to the major axis direction of the elliptically polarized pump beam. Six different sites in Yb:YAG crystal were separated with 30° and 90°, which were responsible for the linearly polarized laser oscillations. Circularly polarized lasers were observed when a Yb:YAG crystal was aligned to a special position between two sites responsible for linearly polarized laser oscillation. Effects of the polarization states of pump source on the laser polarization states of Yb:YAG microchip lasers and polarization direction of different polarized lasers with respect to Yb:YAG crystal rotation was addressed.     

干涉条纹移动的偏振法

本文根据二个椭圆偏振光场进行的理论分析,着重讨论了两个相互正交的圆偏振光(左旋和右旋〕场和一个椭圆偏振光与线偏振光场的特点,以此为基础讨论了干涉条纹移动的偏振法。     

Tuning the polarization states of optical spots at the nanoscale on the Poincaré sphere using a plasmonic nanoantenna

It is shown that the polarization states of optical spots at the nanoscale can be manipulated to various points on the Poincaré sphere using a plasmonic nanoantenna. Linearly, circularly, and elliptically polarized near-field optical spots at the nanoscale are achieved with various polarization states on the Poincaré sphere using a plasmonic nanoantenna. A novel plasmonic nanoantenna is illuminated with diffraction-limited linearly polarized light. It is demonstrated that the plasmonic resonances of perpendicular and longitudinal components of the nanoantenna and the angle of incident polarization can be tuned to obtain optical spots beyond the diffraction limit with a desired polarization and handedness.     

Propagation of polarized light in opals: Amplitude and phase anisotropy

The interaction of linearly polarized light with photonic crystals based on bulk and thin-film synthetic opals is studied. Experimental transmission spectra and spectra showing the polarization state of light transmitted through opals are discussed. A change in polarization is found for waves experiencing Bragg diffraction from systems of crystallographic planes of the opal lattice. It is shown that the polarization plane of the incident linearly polarized wave at the exit from photonic crystals can be considerably rotated. In addition, incident linearly polarized light can be transformed to elliptically polarized light with the turned major axis of the polarization ellipse. Analysis of polarization states of transmitted light by using the transfer-matrix theory and homogenization theory revealed good agreement between calculated and experimental spectra.     

Manipulation of Spontaneous Emission via Quantum Interference in an Elliptically Polarized Laser Field

Manipulation of spontaneous emission from an atom confined in three kinds of modified reservoirs has been investigated by means of an elliptically polarized laser field. Some interesting phenomena such as the multi-peak structure, extreme spectral narrowing, and cancellation of spontaneous emission can be observed by adjusting controllable system parameters. Moreover, these phenomena depend on the constructive or destructive quantum interference between multiple decay channels and which can be changed appreciably by varying the phase difference between the two circularly polarized components of the probe field. These results demonstrate the importance of an elliptically polarized laser field in controlling the spontaneous emission and its potential applications in high-precision spectroscopy.     

Polarization and amplitude optical multistability in a nonlinear ring cavity

The stimulation of a ring cavity filled with an isotropic medium with third order nonlinearity by plane monochromatic arbitrary polarized light is studied. An evolution of the stationary transmission with the change of the polarization of the incident light from circular to linear is discussed. For the linear polarized incident light additional branches of high transmission corresponding to elliptically polarized transmitted light and degenerating with respect to the rotation of the polarization vector are found. The stability of the stationary solutions is discussed. The possibility of the transmitted light polarization and intensity control by changing the polarization ellipticity degree of the incident light is shown.     

修改形式的机械补偿器

为便于产生和分析各种椭圆偏振光 ,需要有产生椭圆偏振光的光学元件 ,其中一个重要的光学元件就是补偿器。补偿器有多种类型 ,在机械补偿器中应用最广泛的是巴俾涅补偿器和索累补偿器 ,但它们各有其缺点。现设计出了一种新的补偿器件 ,它克服了这两种补偿器的不足 ,结构简单、操作方便。     

Theory of polarization phenomena in the hyper-Raman effect

This paper describes a general theory of the polarization state of hyper-Raman emission. In particular an examination is made of the azimuth and ellipticity of hyper-Raman scattered radiation relative to that of a general elliptically polarized source.

It is shown that a distinction may be made between infra-red active and inactive vibrations in the hyper-Raman effect by an analysis of the ellipticity of the scattered light. For a circularly polarized source, the scattering from infra-red inactive vibrations exhibits full reversal of circularity; infra-red active vibrations scatter with no change in circularity. In hyper-Rayleigh scattering a similar analysis is given for non-polar and polar molecules.     

Angular momentum conversion of elliptically polarized beams focused by high numerical-aperture phase Fresnel zone plates

Based on the vectorial Debye theory, we investigate the tight focusing of elliptically polarized light beams by high numerical-aperture (NA) phase Fresnel zone plates (FZP). The conversion of the spin angular momentum (SAM) and the orbital angular momentum (OAM) in the tight focusing of the elliptically polarized beams is investigated in great detail. It is shown that the direction and magnitude of the OAM can be directly modulated by the input polarization, providing effective evidence that the SAM carried by an elliptically polarized light beam is converted into OAM in the tight focusing process. The properties of phase retardation between x and y components of the focused field are also investigated. It is found that focused field of x and y components still keeps its original elliptical polarization state, indicating that the focused field composed of x and y components still carries SAM, whereas the focused field of z component is changed into carrying OAM. The influences of the total zone number and the phase difference of binary phase FZPs with high NA on the intensity distribution in the focal plane are also investigated.     

Orthogonal decomposition of elliptically polarized light through resonators composed of magnetic film

In order to control and analyze light polarization, we design a magnetic resonator and study its transmission properties by the 4×4 transfer matrix method. Through the magnetic resonator an incidence of elliptically polarized light results in two resonance wavelengths. At the two resonance wavelengths, the elliptically polarized light is orthogonally decomposed into left-handed circular polarization and right-handed circular polarization. One of the two circular polarizations is transmitted and the other is reflected.