Showing papers on "Polarization rotator published in 2007"
TL;DR: It is shown that the polarization of the extreme ultraviolet emission depends strongly on the molecular alignment and the orbital structure, and molecular alignment will allow us to produce attosecond pulses with time-dependent polarization.
Abstract: High harmonic emission in isotropic gases is polarized in the same direction as the incident laser polarization. Laser-induced molecular alignment allows us to break the symmetry of the gas medium. By using aligned molecules in high harmonic generation experiments, we show that the polarization of the extreme ultraviolet emission depends strongly on the molecular alignment and the orbital structure. Polarization measurements give insight into the molecular orbital symmetry. Furthermore, molecular alignment will allow us to produce attosecond pulses with time-dependent polarization.
128 citations
TL;DR: In this paper, a laser beam with circular polarization can be converted into either radial or azimuthal polarization by a microfabricated spiral phase plate and a radial (or azimauthal)-type linear analyzer.
Abstract: A laser beam with circular polarization can be converted into either radial or azimuthal polarization by a microfabricated spiral phase plate and a radial (or azimuthal)-type linear analyzer. The resulting polarization is axially symmetric and is able to produce tightly focused light fields beyond the diffraction limit. We describe in detail the theory behind the technique and the experimental verification of the polarization both in the far field and at the focus of a high numerical aperture lens. Vector properties of the beam under strong focusing conditions were observed by comparing the fluorescence images corresponding to the focal intensity distribution for both radial and azimuthal polarizations. The technique discussed here may easily be implemented to a wide range of optical instruments and devices that require the use of tightly focused light beams.
94 citations
TL;DR: A novel method for the electric polarization reversal in TbMnO3 without the application of an electric field or heat is reported.
Abstract: For the memory application of magnetoelectric multiferroics, not only bistability (i.e., ferroelectricity) but also the switching of the polarization direction with some noneverlasting stimulus is necessary. Here, we report a novel method for the electric polarization reversal in TbMnO 3 without the application of an electric field or heat. The direction of the magnetic-field-induced polarization along the a axis (P a ) is memorized even in the zero field where P a is absent. The polarization direction can be reversed by rotating the magnetic-field direction in the ab plane.
86 citations
TL;DR: A design of a polarization converter between linear, circular, and elliptic accomplished with an on-chip high-Q dielectric microring resonator is presented with an optical bistability effect making the polarization of the transmitted light dependent on its spectral or intensity history.
Abstract: We present a design of a polarization converter between linear, circular, and elliptic accomplished with an on-chip high-Q dielectric microring resonator. Nonlinear polarization switching can be accomplished at modest input intensities because of the high-intensity compression in the ring. We predict an optical bistability effect making the polarization of the transmitted light dependent on its spectral or intensity history. © 2007
84 citations
TL;DR: In this article, the authors examined the partial polarization of focused light and demonstrated that the focusing of unpolarized light results in rings of full polarization in the focal plane of the focusing optics.
Abstract: The polarization of light is important in a great variety of optical phenomena, ranging from transmission, reflection and scattering to polarimetric imaging of scenes and quantum-mechanical selection rules of atomic and molecular transitions. Among some less-well-known phenomena that illustrate the vectorial nature of light are the Pancharatnam1 (or geometric2) phase, singularities in the polarization pattern of clear sky3 and polarization of microwave background radiation4. Here, we examine the partial polarization of focused light. We experimentally demonstrate a rather surprising phenomenon, where the focusing of unpolarized light results in rings of full polarization in the focal plane of the focusing optics. The polarization rings are imaged with a resolution of <100 nm by probing the focal region using a gold nanoparticle.
83 citations
TL;DR: A new, to the best of the knowledge, experimental configuration of Mueller matrix polarimeter based on wavelength polarization coding is presented, which is a compact and fast technique to study polarization phenomena.
Abstract: We present a new, to the best of our knowledge, experimental configuration of Mueller matrix polarimeter based on wavelength polarization coding. This is a compact and fast technique to study polarization phenomena. Our theoretical approach, the necessity to correct systematic errors and our experimental results are presented. The feasibility of the technique is tested on vacuum and on a linear polarizer.
75 citations
TL;DR: The use of stress birefringence in the creation of vortex illumination is described and a finite element plane-stress model is used to analyze the space-variant anisotropy.
Abstract: We describe the use of stress birefringence in the creation of vortex illumination. A trifold symmetric stress pattern will provide an annular region that exhibits polarization vortices when illuminated with linearly polarized light and scalar vortices when illuminated with circularly polarized light. A finite element plane-stress model is used to analyze the space-variant anisotropy.
72 citations
TL;DR: Two-dimensional gratings made up of an array of differently twisted nematic structures are obtained by crossed assembling of 1D polarization holograms recorded at the photoaligning substrates that diffract light in different directions with different polarization states that can be optically controlled.
Abstract: Two-dimensional (2D) gratings made up of an array of differently twisted nematic structures are obtained by crossed assembling of 1D polarization holograms recorded at the photoaligning substrates. The rotating linear polarization pattern, produced by the interference of two opposite circularly polarized beams, is recorded on the azo-dye doped polyimide aligning layers. The 2D gratings diffract light in different directions with different polarization states, that can be optically controlled. Orthogonal circularly and linearly polarized diffraction orders are simultaneously obtained irradiating the grating with a linearly polarized beam. An external ac voltage allows to completely control the diffracted energy distribution.
70 citations
Patent•
06 Sep 2007
TL;DR: In this paper, an active eyewear method and system for viewing stereoscopic images is presented, which comprises polarization altering elements, such as twisted nematics, configured to receive light energy and rotate the polarization of light energy passing therethrough, and linear polarizers having polarization axes oriented in substantially identical orientations orthogonal to the first axis of polarization.
Abstract: An active eyewear method and system for viewing stereoscopic images is provided. The eyewear comprises polarization altering elements, such as twisted nematics or super twisted nematics, configured to receive light energy and rotate the polarization of light energy passing therethrough, and linear polarizers having polarization axes oriented in substantially identical orientations orthogonal to the first axis of polarization. The linear polarizers receive light energy from the polarization altering elements. The method comprises transmitting light energy through a sheet polarizer having an first axis of polarization, receiving the light energy with two polarization altering elements, each polarization altering operating out of phase with the other and in synchrony with a video field rate associated with the transmitting, and passing the light energy through two linear polarizers having substantially identical axes of polarization orthogonal to the first axis of polarization.
67 citations
Patent•
15 May 2007
TL;DR: In this paper, the authors present devices and techniques for generating and analyzing states of polarization in light using multiple adjustable polarization rotators in various applications, such as light filtering, illumination, etc.
Abstract: Devices and techniques for generating and analyzing states of polarization in light using multiple adjustable polarization rotators in various applications.
54 citations
TL;DR: This Letter derives sufficiency conditions for the degree of polarization of a beam generated by a uniformly polarized stochastic, electromagnetic source of a wide class to be the same throughout the far zone and in the source plane.
Abstract: It has been known for some time that the degree of polarization of a light beam may change on propagation, even in free space. In this Letter we derive sufficiency conditions for the degree of polarization of a beam generated by a uniformly polarized stochastic, electromagnetic source of a wide class to be the same throughout the far zone and in the source plane.
29 Mar 2007
TL;DR: Two mode-evolution-based low-loss compact-size integrated polarization rotators and transformers are presented that can achieve complete polarization rotations and transformations between different classes of waveguide modes with a device length of tens of micrometers and with a negligible insertion loss.
Abstract: Two mode-evolution-based low-loss compact-size integrated polarization rotators and transformers are presented. They are designed to fulfill the tasks of rotating mode polarizations between Gaussian-like strip waveguide modes and non-Gaussian-like slotted waveguide modes, as well as the mode transforming between horizontal and vertical slotted waveguides. Consisting of several adiabatic tapers, the presented devices can achieve complete polarization rotations and transformations between different classes of waveguide modes with a device length of tens of micrometers and with a negligible insertion loss.
TL;DR: Both the theoretical and experimental results show that the polymer coating layer has a significant influence on the polarization dependence of bend loss.
Abstract: Polarization dependence of bend loss caused by the polymer coating layer for a standard singlemode fiber (SMF28) is investigated theoretically and experimentally. Bend loss for SMF28 for both the TE and TM mode is calculated separately. Normalized polarization dependent loss is proposed for the characterization of the polarization sensitivity of bend loss for different bend radii. Corresponding experimental tests are presented, which agree with the theoretical results. Both the theoretical and experimental results show that the polymer coating layer has a significant influence on the polarization dependence of bend loss.
TL;DR: In this paper, the authors demonstrated the generation of a radially polarized laser beam using the birefringence of a c-cut Nd:GdVO4 laser crystal.
Abstract: We demonstrated the generation of a radially polarized laser beam using the birefringence of a c-cut Nd:GdVO4 laser crystal. Compared with a previous work using a long Nd:YVO4 crystal, an improvement of the power efficiency and a reduction of the cavity size were achieved. A larger expansion of the cavity length for an extraordinary ray due to the positive birefringence of the crystal was numerically evaluated on the basis of ray optics and the vector diffraction theory.
TL;DR: In this article, a geometrical model based on the concept of dynamic eigenstates of polarization is proposed to describe the behavior of nonlinear polarization rotation arising in semiconductor optical amplifiers.
Abstract: We propose a geometrical model based on the concept of dynamic eigenstates of polarization to describe the behavior of nonlinear polarization rotation (NPR) arising in semiconductor optical amplifiers (SOAs). The rotation axis with respect to either the bias current or the optical power variation is demonstrated on the Poincare sphere (PS), meanwhile a procedure to find the rotation axis is presented. Thus, the SOA-based NPR with linear polarization maintenance (zero polarization ellipticity angle) can be achieved experimentally. The rotation of polarization azimuth on the PS with respect to the bias current, the probe signal power, and the pump signal power variation is measured experimentally. The 180deg phase difference between the transverse electric and the transverse magnetic modes can be all achieved with linear polarization maintenance.
TL;DR: In this paper, a pure frequency-induced polarization bistability in a vertical-cavity surface-emitting laser (VCSEL) subject to orthogonal optical injection was investigated.
Abstract: We report theoretically on a pure frequency-induced polarization bistability in a vertical-cavity surface-emitting laser (VCSEL) subject to orthogonal optical injection, i.e., the master laser light polarization is orthogonal to that of the slave VCSEL. As the frequency detuning is scanned from negative to positive values and for a fixed injected power, the VCSEL exhibits two successive and possibly bistable polarization switchings. The first switching (from the slave laser polarization to the injected light polarization) exhibits a bistable region whose width is maximum for a given value of the injected power. Such a dependency of hysteresis width on the injected power is similar to that recently found experimentally by Hong et al.[Electron. Lett. 36, 2019 (2000)]. The bistability accompanying the second switching (from the injected light polarization back to the slave laser free-running polarization) exhibits, however, significantly different features related to the occurrence of optical chaos. Interestingly, the width of the bistable region can be tuned over a large range not only by modifying the injection parameters but also by modifying the device parameters, in particular the VCSEL linewidth enhancement factor.
TL;DR: In this paper, a single crystal BaTiO3 nanowire along its length axis was used for direct ferroelectric polarization switching under axial dc bias, monitored with lateral mode piezoresponse force microscopy, was shown to be non-remnant.
Abstract: We report the study of direct ferroelectric polarization switching of a single crystal BaTiO3 nanowire along its length axis. Polarization switching under axial dc bias, monitored with lateral mode piezoresponse force microscopy, was shown to be non-remnant. The result suggested the existence of a preferred polarization orientation in BaTiO3 nanowire, i.e., a polarization imprint, and was explained with a core–shell polarization structure model. The polarization shell thickness was estimated to be ~10 nm for a BaTiO3 nanowire having a thickness of ~120 nm.
Patent•
NEC1
TL;DR: In this paper, a first waveguide, a second waveguide and a third waveguide are used at the same time to perform wave-guiding to a single waveguide in an optical circuit, where large aspect ratio directions of corresponding ends of a core of one core and another core differ from each other.
Abstract: An optical circuit comprises: a first waveguide; a second waveguide: and a third waveguide that converts mode field and direction of polarization of light of said first waveguide at the same time to perform wave guiding to said second waveguide: wherein large aspect ratio directions of corresponding ends of a core of said first waveguide and a core of said second waveguide differ from each other.
TL;DR: A measure of the degree of polarization for the three-dimensional polarization matrix (coherence matrix) of an electromagnetic field is proposed, based on Rayleigh scattering, which gives a well-defined purity measure, which is not a unitary invariant of the matrix.
Abstract: A measure of the degree of polarization for the three-dimensional polarization matrix (coherence matrix) of an electromagnetic field is proposed, based on Rayleigh scattering. The degree of polarization at a point is defined as an average, over all scattering directions, of an imagined dipole scattering of the three-dimensional state of polarization. This gives a well-defined purity measure, which, unlike other proposed measures of the three-dimensional degree of polarization, is not a unitary invariant of the matrix. This is demonstrated and discussed for several examples, including a partially polarized transverse beam.
TL;DR: A polarization-enhancing reflector design is reported, which is matched to the emission characteristics of GaInN/GaN 460 nm light-emitting diodes grown on (0001) oriented sapphire substrates, and the numerical algorithm used to generate the optimized shape is described.
Abstract: A polarization-enhancing reflector design, which is matched to the emission characteristics of GaInN/GaN 460 nm light-emitting diodes grown on (0001) oriented sapphire substrates, is reported. Side-emitted light from these devices is known to be highly polarized with the electric field in the plane of the active region. Through selective rotation of polarization by the reflector, the in-plane polarized side-emitted light is directed upwards with a single dominant linear polarization. Polarization ratios as high as 3.5:1 are measured in the farfield, and the average polarization ratio is 1.9:1. If only light that strikes the reflector is considered, the polarization ratio is 2.5:1. The concept of the polarization-enhancing reflector and the numerical algorithm used to generate the optimized shape are also described.
TL;DR: Shaping of the phase, amplitude, and polarization state of an ultrashort pulse is demonstrated using a novel arrangement of a single, linear, high-resolution liquid crystal array.
Abstract: Shaping of the phase, amplitude, and polarization state of an ultrashort pulse is demonstrated using a novel arrangement of a single, linear, high-resolution liquid crystal array. Orthogonal polarization components, separated by a Wollaston prism, are manipulated independently and re-combined in a near-common path, common-optic geometry.
TL;DR: In this paper, the relationship between real and imaginary parts of the complex polarization angle and polarization ellipse parameters is established, which governs the evolution of the polarization along the curvilinear ray.
TL;DR: In this article, the dependence of fluorescence depletion on the relative polarizations of pump and erase beams was investigated for a sample of randomly oriented Rhodamine-6G molecules, and the significance of polarization effects was illustrated for two existing systems of fluorescent super-resolution microscopy: a circular polarization setup and an azimuth-linear polarization setup.
Journal Article•
TL;DR: In this article, a measure of the degree of polarization for the three-dimensional polarization matrix (coherence matrix) of an electromagnetic field is proposed, based on Rayleigh scattering, which is defined as an average, over all scattering directions, of an imagined dipole scattering of the 3D state of polarization.
Abstract: A measure of the degree of polarization for the three-dimensional polarization matrix (coherence matrix) of an electromagnetic field is proposed, based on Rayleigh scattering. The degree of polarization at a point is defined as an average, over all scattering directions, of an imagined dipole scattering of the three-dimensional state of polarization. This gives a well-defined purity measure, which, unlike other proposed measures of the three-dimensional degree of polarization, is not a unitary invariant of the matrix. This is demonstrated and discussed for several examples, including a partially polarized transverse beam.
TL;DR: A new method for measuring the birefringence dispersion in polarization-maintaining fibers (PMFs) with high sensitivity and accuracy is presented, employing white-light interferences between two orthogonally polarized modes of PMFs.
Abstract: A new method for measuring the birefringence dispersion in polarization-maintaining fibers (PMFs) with high sensitivity and accuracy is presented. The method employs white-light interferences between two orthogonally polarized modes of PMFs. The group birefringence of the fiber is calibrated first. Then the birefringence dispersion and its variation along different fiber sections are acquired by analyzing the broadening of interferograms at different fiber lengths. The main sources of error are investigated. Birefringence dispersions of two PANDA fibers at their operation wavelength are measured to be 0.011 ps/(km nm) and 0.018 ps/(km nm). A measurement repeatability of 0.001 ps/(km nm) is achieved.
TL;DR: A polarization rotator based on angled waveguides in the InP/InGaAsP material system is presented, a prime candidate for use in an integrated polarization diversity scheme.
Abstract: We present the design, fabrication, and operation of a polarization converter based on angled waveguides in the InP/InGaAsP material system. By combining design elements from mode evolution and birefringent devices, the total device length is kept short (less than 50μm) and the insertion efficiency high at 81%+/-19%, which corresponds to an insertion loss of 1dB. Devices operate broadband, i.e., the polarization conversion exceeds 15dB over a 100nm wavelength range. A polarization rotator with these specifications is a prime candidate for use in an integrated polarization diversity scheme.
TL;DR: In this paper, the polarization state of the BESSY UE56/1-PGM beamline radiation in the broad wavelength range of 12.7-15.5nm was measured using a molybdenum/silicon transmission phase retarder and a reflection analyzer with aperiodic multilayer interference structures, which can broaden the spectral response of these optical elements.
Abstract: The polarization state of the BESSY UE56/1-PGM beamline radiation in the broad wavelength range of 12.7–15.5nm was measured using a molybdenum/silicon transmission phase retarder and a reflection analyzer with aperiodic multilayer interference structures, which can broaden the spectral response of these optical elements. The characteristics of the circular polarized undulator radiation, as well as the polarization properties of the two polarizing elements, were determined by a complete polarization analysis. Furthermore, the polarization of the radiation as a function of the undulator shift setting was also measured at the wavelength of 13.1nm by use of the broadband phase retarder-analyzer pair.
TL;DR: A novel configuration for a twisted-nematic liquid-crystal display (TN-LCD) that makes it operate as a controllable polarization rotator using a zero-twist LCD inserted between two quarter-wave plates is presented.
Abstract: We present a novel configuration for a twisted-nematic liquid-crystal display (TN-LCD) that makes it operate as a controllable polarization rotator. We extend a previously reported polarization rotator configuration using a zero-twist LCD inserted between two quarter-wave plates. We first operate the TN-LCD in the polarization eigenvector configuration and show how this system can act as an equivalent voltage-controlled wave plate. Next we incorporate this wave plate into the optical rotator configuration. We show that the plane of polarization of the transmitted light can be rotated as a function of the phase introduced by the display. Finally, we create a 2D polarization mask where different areas of the TN-LCD form different polarization states. Experimental results are included.
01 Oct 2007
TL;DR: In this article, the evolution of the degree of polarization is determined by the interplay between the coherence properties of the pulse and fiber birefringence, and it is shown that the pulse polarization changes of statistical pulses in single-mode fibers.
Abstract: We consider polarization changes of statistical pulses in single-mode fibers. We show that, the evolution of the degree of polarization is determined by the interplay between the coherence properties of the pulse and fiber birefringence.