Orthogonal Elliptical Polarization Research Articles

Faithful reconstruction in orthogonal elliptical polarization holography read by different polarized waves.

A potential technology applied in optical storage, the polarization holography has attracted much attention. In polarization holography, not only the amplitude and phase but also the polarization state is applied to record the information. What is meant by faithful reconstruction is that the reconstructed wave is identical to the signal wave. In the previously reported experiments about faithful reconstruction in orthogonal polarization holography, all the reading waves are identical to the reference waves of recording stage. It may result in a misunderstanding that the reading wave being identical to the reference wave of recording stage is the prerequisite for faithful reconstruction. We designed the experiments to observe the faithful reconstruction read by different polarized waves, where two orthogonal elliptically polarized waves are applied in the recording stage and phenanthrenequinone-doped poly methyl methacrylate (PQ/PMMA) is used as the recording material. By controlling the exposure time of recording material, the faithful reconstruction may be observed when the reading wave is the linearly polarized wave and the elliptically polarized wave, where neither reading wave is the same as the reference wave. The result may be of help for us to understand the reconstructed characteristics of orthogonal polarization holography.

Null reconstruction in orthogonal elliptical polarization holography read by non-orthogonal reference wave

Based on the newly developed tensor holography theory, the null reconstruction in orthogonal elliptical polarization holography is reported. In the recording stage, the information is stored in the recording material by two orthogonal elliptical polarization waves. In the reconstructing stage, the variation of the power of reconstructed wave with the polarization state of reading wave is studied. Then the null reconstruction, the reconstructed wave being identical to zero, is observed when the reading wave is the non-orthogonal reference wave of recording stage. However, in those previously reported experiments, when and only when the recording material is illuminated by the orthogonal reference wave, the null reconstruction could be observed. Thus, our result is very different from the previously reported results and would change the perspective on the null reconstruction. Based on the tensor theory, we analyze the condition for null reconstruction in orthogonal polarization holography. For the null reconstruction in orthogonal linear polarization holography, the reading wave should be the orthogonal reference wave. However, for the null reconstructions in orthogonal circular and elliptical polarization holography, the reading wave may be the non-orthogonal reference wave. We think the result may enlarge our knowledge about the null reconstruction.

Prerequisite for faithful reconstruction of orthogonal elliptical polarization holography

Faithful reconstruction, which is a key phenomenon in optical data storage, is significant in polarization holography and has attracted much attention. It is defined as the reconstructed wave being identical to the signal wave. We design an experiment to observe the faithful reconstruction of elliptical polarization holography in which the two orthogonal elliptical polarization waves are applied in the recording stage. In the experiment, phenanthrenequinone-doped poly methyl methacrylate is used as the recording material, and the angle between the signal and reference waves is ∼56 deg. We control the exposure time of recording material to observe the faithful reconstruction of orthogonal elliptical polarization holography. How to obtain the faithful reconstruction is interesting work; therefore, we propose a prerequisite for faithful reconstruction. Although the prerequisite is derived from orthogonal elliptical polarization holography, it could also be applied in orthogonal linear and circular polarization holography. The result may be helpful for understanding the faithful reconstruction of orthogonal polarization holography.

Investigation of the null reconstruction effect of an orthogonal elliptical polarization hologram at a large recording angle

We report on the null reconstruction effect (NRE) of an elliptical polarization volume hologram with orthogonal elliptically, circularly, and linearly polarized waves, respectively. The NRE is a special phenomenon in polarization holography, which means the diffraction efficiency declines to zero when the hologram is reconstructed by an orthogonally polarized reading wave. In our previous work [Opt. Express24, 1641 (2016)OPEXFF1094-408710.1364/OE.24.001641; Opt. Lett.42, 1377 (2017)OPLEDP0146-959210.1364/OL.42.001377; Opt. Express23, 8880 (2015)OPEXFF1094-408710.1364/OE.23.008880], the NRE of polarization holography recorded by linear and circular polarization waves has been investigated. Compared with linear and circular polarization holography, elliptical polarization holography represents a more general and unified recording hologram. However, no work on the NRE of elliptical polarization holography, as far as we know, has been reported until now. In this paper, the NRE of elliptical polarization holography is investigated and demonstrated theoretically and experimentally. First, the conditions of achieving NRE in elliptical polarization holography are studied based on vector holography theory. The results indicate that the NRE is a common phenomenon in polarization holography written by linear, circular, and elliptical polarization waves. Then, a series of experiments of NRE in a polarization hologram written by orthogonal elliptically, circularly, and linearly polarized waves is carried out. The NRE of elliptical polarization holography is experimentally observed, and the results are in nice agreement with the theoretical analysis. The NRE of elliptical polarization holography is expected to be applied in high-density optical data storage and polarization-controlled holographic elements.

Collinear Acousto-Optical Transformation of Bessel Light Beams in Biaxial Gyrotropic Crystals

The collinear acousto-optical transformation of Bessel light beams in biaxial gyrotropic crystals into two annular, internal conical refraction beams with orthogonal elliptical polarization is studied. It is found that the diffraction efficiency is maximal (~50–60%) for low ultrasound intensities and varies slightly with further increases in acoustic power. At high ultrasound intensities, the intensities of the transmitted and diffracted annular beams differ insignificantly. The possible use of this acousto-optical interaction for creating collinear tuneable narrow-band acousto-optical filters at low ultrasonic frequencies is demonstrated.

Statistics of the individual-pulse polarization based on propagation effects in the pulsar magnetosphere

Pulsar radio emission is modelled as a sum of two completely polarized non-orthogonal modes with the randomly varying Stokes parameters and intensity ratio. The modes are the result of polarization evolution of the original natural waves in the hot, magnetized, weakly inhomogeneous plasma of the pulsar magnetosphere. In the course of the wavemode coupling, the linearly polarized natural waves acquire purely orthogonal elliptical polarizations. Further on, as the waves pass through the cyclotron resonance, they become non-orthogonal. The pulse-to-pulse fluctuations of the final polarization characteristics and the intensity ratio of the modes are attributed to the temporal fluctuations in the plasma flow. The model suggested allows one to reproduce the basic features of the one-dimensional distributions of the individual-pulse polarization characteristics. Besides that, the propagation origin of the pulsar polarization implies a certain correlation between the mode ellipticity and position angle. On a qualitative level, for different sets of parameters, the expected correlations appear compatible with the observed ones. Further theoretical studies are necessary to establish the quantitative correspondence of the model to the observational results and to develop a technique of diagnostics of the pulsar plasma on this basis.

Spatial-multimode broadband squeezing in both polarization components of an electromagnetic field.

The three-wave parametric down-conversion in an uniaxial crystal with type-II phase matching is considered. It is established that by these conditions the spatial-multimode broadband squeezed states of light are generated with two orthogonal elliptical polarizations. The eigen-polarization-vectors of multimode squeezed light on the entry and at the exit of the crystal are found. It is shown that the homodyne reception of such light can reduce the photodetection noise of the surface current density below the shot noise in some time and space regions for both eigen-polarization-vectors of light. The frequency and spatial-frequency spectrum of the current density for both eigen-polarization-vectors is calculated. A clear explanation of multimode squeezing for both polarizations is given.

Accurate method to determine the eigenstates of polarization in gyrotropic media

Many practical modulator materials include combinations of electrooptically induced birefringence, optical activity, and/or Faraday rotation. Thus, there is a need for a procedure to design and analyze devices fabricated with materials exhibiting any or all of these effects. In this paper a simple procedure employing an extension of the general Jacobi method is introduced for determining the properties of the two allowed elliptical eigenpolarizations for an arbitrary direction of propagation and for the principal indices and axes of a general lossless, electrooptic, and gyrotropic medium. The procedure uses an iterative application of unitary transformations to diagonalize the Hermitian impermeability tensor. A complex polarization variable is defined from elements of the unitary transformation matrix to determine the ellipticity, azimuth angle, relative amplitude and phase, and handedness of the two orthogonal elliptical polarizations. The phase velocity indices of refraction are readily calculated with simple derived expressions. The procedure is numerically stable and accurate for any crystal class, external field direction, and direction of propagation.

Division-of-wave-front thin-film beam splitter for generating binary patterns of orthogonal elliptical polarization states

A division-of-wave-front thin-film beam splitter is described that reflects monochromatic light at oblique incidence with orthogonal elliptical polarization states. It consists of a metallic substrate partially covered with a transparent thin film that inverts the ratio ρ of the complex p and s reflection coefficients at the principal angle of the metal. Any pattern of coated and uncoated areas of the substrate is imprinted upon the reflected wave front as a corresponding two-dimensional spatial binary polarization pattern. A specific design is given that uses a Au substrate at a wavelength of 632.8 nm. The effects of small errors in the film refractive index, the film thickness, and the angle of incidence are discussed. It is noted that a layer that inverts ρ at a certain (especially high) angle of incidence is an effective ρ-inverting layer at all angles.

Elliptically Polarized Natural Modes in Pulsar Magnetospheres

The most obvious feature of the polarization of the radio emission from most pulsars is the rotation of the plane of linear polarization across pulses. The original interpretation of this in terms of the magnetic pole model (Radhakrishnan 1969, Radhakrishnan et al. 1969, Radhakrishnan and Cooke 1969) accounts for the variation of position angle extremely well for some pulsars (e.g. Manchester and Taylor 1977, Manchester 1978). Conversely, this provides strong support for the magnetic pole model for pulsar emission. It also suggests that the emission is basically linearly polarized as implied by virtually all proposed emission mechanisms, e.g. the reviews by Ginzburg and Zheleznyakov (1975) and Arons (1979). However, there are two features of the polarization which require a separate explanation. First, some pulsars have a moderately high degree of circular polarization, even in the integrated pulse profile (Manchester 1971, Lyne, Smith and Graham 1971). In some pulsars the average degree of circular polarization can exceed the average degree of linear polarization, e.g. in PSR 0835-41 and 0959-54 (McCulloch et al. 1978). Second, some pulsars exhibit the phenomenon of transitions between orthogonal elliptical polarizations (Manchester, Taylor and Huguenin 1975, Backer, Rankin and Campbell 1976, Cordes and Hankins 1977, Cordes, Rankin and Backer 1978). In many pulsars the orthogonal polarizations have substantial circular components, e.g. in PSR 1133 + 16 (Manchester et al. 1975) and PSR 2020 + 28 (Cordes et al. 1978).