Showing papers on "Polarization rotator published in 2011"
TL;DR: In this paper, the authors demonstrate the generation of optical vortices with radial or azimuthal polarization using a space variant polarization converter, fabricated by femtosecond laser writing of self-assembled nanostructures in silica glass.
Abstract: We demonstrate the generation of optical vortices with radial or azimuthal polarization using a space variant polarization converter, fabricated by femtosecond laser writing of self-assembled nanostructures in silica glass. Manipulation of the induced form birefringence is achieved by controlling writing parameters, in particular, the polarization azimuth of the writing beam. The fabricated converter allows switching from radial to azimuthal polarization by controlling the handedness of incident circular polarization.
457 citations
TL;DR: A novel ultra-short polarization beam splitter (PBS) based on a bent directional coupler is proposed by utilizing the evanescent coupling between two bent optical waveguides with different core widths.
Abstract: A novel ultra-short polarization beam splitter (PBS) based on a bent directional coupler is proposed by utilizing the evanescent coupling between two bent optical waveguides with different core widths. For the bent directional coupler, there is a significant phase-mismatch for TE polarization while the phase-matching condition is satisfied for TM polarization. Therefore, the TM polarized light can be coupled from the narrow input waveguide to the adjacent wide waveguide while the TE polarization goes through the coupling region without significant coupling. An ultra-short ( 10dB.
206 citations
TL;DR: This work presents an idea to generate an arbitrary space-variant vector beam with structured polarization and phase distributions, synthesized from the left- and right-hand polarized light, each carrying different phase distributions.
Abstract: We present an idea to generate an arbitrary space-variant vector beam with structured polarization and phase distributions. The vector beams are synthesized from the left- and right-hand polarized light, each carrying different phase distributions. Both the phase and the state of polarization of vector beams can be tailored independently and dynamically by a spatial light modulator.
194 citations
TL;DR: A polarization rotator based on adiabatic mode evolution on silicon for polarization-diversified circuits and combined with a compact, broadband polarization beam splitter based on cascaded directional couplers enhances the polarization conversion extinction ratio to over 30 dB with less than 1.5 dB total insertion loss over a 60 nm spectral range.
Abstract: We demonstrate a polarization rotator based on adiabatic mode evolution on silicon for polarization-diversified circuits. The rotator has a device length of 420 μm, a polarization-conversion efficiency of more than 90%, and an insertion loss less than 1 dB for a wavelength range of 80 nm. Combining the rotator with a compact, broadband polarization beam splitter based on cascaded directional couplers enhances the polarization conversion extinction ratio to over 30 dB with less than 1.5 dB total insertion loss over a 60 nm spectral range.
143 citations
12 Dec 2011
TL;DR: P polarization field displays are introduced as an optically-efficient design for dynamic light field display using multi-layered LCDs and achieve increased brightness, higher resolution, and extended depth of field, as compared to existing automultiscopic display methods for dual-layer and multi-layer LCDs.
Abstract: We introduce polarization field displays as an optically-efficient design for dynamic light field display using multi-layered LCDs. Such displays consist of a stacked set of liquid crystal panels with a single pair of crossed linear polarizers. Each layer is modeled as a spatially-controllable polarization rotator, as opposed to a conventional spatial light modulator that directly attenuates light. Color display is achieved using field sequential color illumination with monochromatic LCDs, mitigating severe attenuation and moire occurring with layered color filter arrays. We demonstrate such displays can be controlled, at interactive refresh rates, by adopting the SART algorithm to tomographically solve for the optimal spatially-varying polarization state rotations applied by each layer. We validate our design by constructing a prototype using modified off-the-shelf panels. We demonstrate interactive display using a GPU-based SART implementation supporting both polarization-based and attenuation-based architectures. Experiments characterize the accuracy of our image formation model, verifying polarization field displays achieve increased brightness, higher resolution, and extended depth of field, as compared to existing automultiscopic display methods for dual-layer and multi-layer LCDs.
123 citations
TL;DR: In this paper, an overview of the state of the art and the latest results for cutting, welding and drilling achieved at the IFSW of the University of Stuttgart is presented.
118 citations
TL;DR: An electrically thin chiral metamaterial structure composed of four U-shaped split ring resonator pairs is utilized in order to realize polarization rotation that is dependent on the polarization of the incident wave at 6.2 GHz.
Abstract: An electrically thin chiral metamaterial structure composed of four U-shaped split ring resonator pairs is utilized in order to realize polarization rotation that is dependent on the polarization of the incident wave at 6.2 GHz. The structure is optimized such that a plane wave that is linearly polarized at an arbitrary angle is an eigenwave of the system at this frequency. The analytical relation between the incident polarization and the polarization rotation is derived using transmission matrices. Furthermore, the proposed structure exhibits an asymmetric transmission of linearly polarized waves at 6.2 GHz. Plane waves traveling in opposite but perpendicular directions to the material plane are rotated by different angles. On the other hand, four incident polarization angles have been found for the same structure, at which the transmission is symmetric. The experiment results are in good agreement with the numerical results.
110 citations
TL;DR: The first measurement of the spin Hall effect of light (SHEL) on an air-metal interface is reported, which is a polarization-dependent out-of-plane shift on the reflected beam.
Abstract: We report the first measurement of the spin Hall effect of light (SHEL) on an air-metal interface. The SHEL is a polarization-dependent out-of-plane shift on the reflected beam. For the case of metallic reflection with a linearly polarized incident light, both the spatial and angular variants of the shift are observed and are maximum for -45°/45° polarization, but zero for pure s and p polarization. For an incoming beam with circular polarization states however, only the spatial out-of-plane shift is present.
88 citations
TL;DR: It is found that the polarization is spatially varying and entirely transversally polarized, and the polarization singularity disappears at the beam center, which makes the central bright channel possible.
Abstract: Generation of a nondiffracting transversally polarized beam by means of transmitting an azimuthally polarized beam through a multibelt spiral phase hologram and then highly focusing by a high-NA lens is presented. A relatively long depth of focus (∼4.84λ) of the electric field with only radial and azimuthal components is achieved. The polarization of the wavefront near the focal plane is analyzed in detail by calculating the Stokes polarization parameters. It is found that the polarization is spatially varying and entirely transversally polarized, and the polarization singularity disappears at the beam center, which makes the central bright channel possible.
84 citations
TL;DR: In this article, a single-photon optical diode can be achieved by coupling a quantum impurity to a passive, linear optical waveguide which possesses a locally planar, circular polarization.
Abstract: A single-photon optical diode operates on individual photons and allows unidirectional propagation of photons. By exploiting the unique polarization configuration in a waveguide, we show here that a single-photon optical diode can be accomplished by coupling a quantum impurity to a passive, linear optical waveguide which possesses a locally planar, circular polarization. We further show that the diode provides a near unitary contrast for an input pulse with finite frequency bandwidth and can be implemented in a variety of types of waveguides. Moreover, the performance of the diode is not sensitive to the intrinsic dissipation of the quantum impurity.
78 citations
TL;DR: The degradation of polarization entanglement is characterized theoretically and experimentally and the highest PMD tolerance is achieved when the bandwidth of the pump used to generate the entangled photons in a χ((3)) process is approximately half the bandwidth in the quantum channels.
Abstract: We characterize theoretically and experimentally the degradation of polarization entanglement in a fiber-optic entanglement distribution system where one of the optical fibers is exposed to the effects of polarization mode dispersion (PMD). We show gradual reduction of entanglement with increasing PMD and find that the highest PMD tolerance is achieved when the bandwidth of the pump used to generate the entangled photons in a χ(3) process is approximately half the bandwidth of the quantum channels.
TL;DR: In this paper, the optical response of polarization sensitive materials is studied on the basis of a model in which the materials consist of rod molecules that are oriented in random directions and the photoinduced change of the dielectric tensor is expressed as a function of the electric field in a general form.
Abstract: The optical response of polarization sensitive materials is studied on the basis of a model in which the materials consist of rod molecules that are oriented in random directions. The photoinduced change of the dielectric tensor is expressed as a function of the electric field in a general form. Using this expression, we derive the vectorial coupled wave equations in volume polarization holograms. We discuss the basic properties of polarization holograms.
TL;DR: In this paper, the relative intensity fluctuations for a variable set of orthogonal elliptic polarization components of a linearly polarized laser beam traversing a resonant resonance cell were studied.
Abstract: We have studied relative-intensity fluctuations for a variable set of orthogonal elliptic polarization components of a linearly polarized laser beam traversing a resonant ${}^{87}$Rb vapor cell. Significant polarization squeezing at the threshold level ($\ensuremath{-}3$dB) required for the implementation of several continuous-variable quantum protocols was observed. The extreme simplicity of the setup, which is based on standard polarization components, makes it particularly convenient for quantum information applications.
TL;DR: In this article, a 3-μm-long ultrasmall surface plasmon polariton effect-based transverse-magnetic (TM) mode to transverseelectric (TE) mode polarization rotator was demonstrated both theoretically and experimentally.
Abstract: A 3-μm-long ultrasmall surface plasmon polariton-effect-based transverse-magnetic (TM) mode to transverse-electric (TE) mode polarization rotator was demonstrated both theoretically and experimentally. Effective polarization rotation with 11-dB polarization extinction ratio (PER) was achieved in fabricated devices. The insertion loss at the transition region was about 11 dB.
TL;DR: In this article, a toolset of waveguide elements, which can be combined to produce polarization functional devices in a single contiguous waveguide, is examined, and a full-vectorial modesolver is used to determine the modes in a number of example III-V waveguide structures, and the polarization state evolution is considered by using an averaged Stokes vector illustrated on the Poincare sphere construct.
Abstract: A toolset of waveguide elements is examined, which can be combined to produce polarization functional devices in a single contiguous waveguide. In particular, waveguide implementations of an optical isolator and a polarization modulator are discussed. The waveguide elements, i.e., quasi-phase-matched nonreciprocal polarization mode converter, reciprocal polarization mode converter (R-PMC), and a differential phase shifter, are all based on mode beating. A universal 3-dB R-PMC specification is identified, which suffices for all the polarization functional devices considered here. A full-vectorial modesolver is used to determine the modes in a number of example III-V waveguide structures, and the polarization state evolution is considered by using an averaged Stokes vector illustrated on the Poincare sphere construct.
TL;DR: Using a combination of internal conical diffraction and Mach-Zehnder interferometry, an efficient new technique is theoretically and experimentally demonstrated for the conversion of a linearly polarized Gaussian laser beam to one with radial polarization.
Abstract: Using a combination of internal conical diffraction and Mach-Zehnder interferometry we have theoretically and experimentally demonstrated an efficient new technique for the conversion of a linearly polarized Gaussian laser beam to one with radial polarization. These methods that can be adapted to yield either ring-shaped or first order Bessel beams which are radially polarized.
TL;DR: The effectiveness of nonlocal compensation for polarization mode dispersion while taking into account the possibility that entanglement is generated through the use of a pulsed optical pump signal is quantified.
Abstract: We study the feasibility of nonlocally compensating for polarization mode dispersion (PMD), when polarization entangled photons are distributed in fiber-optic channels. We quantify the effectiveness of nonlocal compensation while taking into account the possibility that entanglement is generated through the use of a pulsed optical pump signal.
TL;DR: A novel design of a polarization rotator based on silica photonic crystal fiber that can provide a nearly 100% polarization conversion ratio with a device length of 3102 μm is proposed and analyzed.
Abstract: We propose and analyze a novel (to the best of our knowledge) design of a polarization rotator (PR) based on silica photonic crystal fiber. The proposed design has a rectangular core region with a slanted sidewall. The simulation results are obtained using the full vectorial finite difference method as well as the full vectorial finite difference beam propagation method. The numerical results reveal that the suggested PR can provide a nearly 100% polarization conversion ratio with a device length of 3102 μm.
TL;DR: In this paper, a polarization beam splitter based on a self-collimation Mach-Zehnder interferometer (SMZI) in a hole-type silicon photonic crystal was proposed and numerically demonstrated.
TL;DR: In this article, the authors proposed a compact all-in-fiber dynamic polarization controller based on index-guiding soft-glass photonic crystal fibers infiltrated with nematic liquid crystals.
Abstract: Compact polarization control elements based on index-guiding soft-glass photonic crystal fibers infiltrated with nematic liquid crystals are proposed and thoroughly studied. The nematic director profiles at the fiber's cross section are consistently calculated by solving the coupled electrostatic and elastic problem, in the context of an analysis on the tunability of liquid-crystal-infiltrated photonic crystal fibers. The fiber's dispersive properties and light propagation in the proposed polarization controller are studied by means of a fully anisotropic finite-element-based beam propagation method. The electrically induced evolution of the state of polarization is mapped on the Poincare sphere. Efficient polarization conversion is demonstrated, with a crosstalk of -50 dB, for a total device length of 4.65 mm and a maximum applied voltage of 150 V. Crosstalk values lower than -20 dB are achieved over a 30 nm window. The proposed devices are envisaged as compact all-in-fiber dynamic polarization controllers.
TL;DR: In this article, a novel design of high-tunable polarization rotator based on soft glass photonic crystal fiber (PCF) is introduced and analyzed, which has a central hole infiltrated with nematic liquid crystal.
Abstract: A rigorous study of polarization rotation in a novel design of high-tunable polarization rotator based on soft glass photonic crystal fiber (PCF) is introduced and analyzed. The suggested PCF has a central hole infiltrated with nematic liquid crystal. At a wavelength of 1.55 μm, nearly 100% polarization conversion ratio is obtained, with a device length of 558 μm. The simulation results are evaluated using the full-vectorial finite-difference method along with the full-vectorial finite-difference beam propagation method.
TL;DR: It is demonstrated that complex media may confer high degree of local polarization (0.75 DOP average) to the incident unpolarized light.
Abstract: The polarization of a coherent depolarized incident light beam passing through a scattering medium is investigated at the speckle scale The polarization of the scattered far field at each direction and the probability density function of the degree of polarization are calculated and show an excellent agreement with experimental data It is demonstrated that complex media may confer high degree of local polarization (075 DOP average) to the incident unpolarized light
TL;DR: It is shown that there exists an optimum pump power leading to a maximum degree of polarization, which is proportional to the pump power and changes with the signal wavelength, following the Raman gain shape.
Abstract: The Raman gain based polarization pulling process in a copropagating scheme is investigated. We map the degree of polarization, the angle between the signal and pump output Stokes vectors, the mean signal gain and its standard deviation considering the entire Raman gain bandwidth. We show that, in the undepleted regime (signal input power ∼ 1 μW), the degree of polarization is proportional to the pump power and changes with the signal wavelength, following the Raman gain shape. In the depleted regime (signal input power ≳ 1mW), the highest values for the degree of polarization are no more observed for the highest pump powers. Indeed, we show that exists an optimum pump power leading to a maximum degree of polarization.
TL;DR: The complete polarization state generator (PSG) as mentioned in this paper consists of one rotatable polarizer and one variable retarder with a quarter-wave plate, which is employed in the quantitative orientationindependent differential polarization microscope, which uses polarized light states with the same ellipticity and different orientation angles.
Abstract: The complete polarization state generator (PSG), which consists of one rotatable polarizer and one variable retarder with a quarter-wave plate, is introduced. The orientation angle of its output polarization ellipse equals half of the retardance of the variable retarder, and the ellipticity angle corresponds to the polarizer azimuth. The PSG is employed in the quantitative orientation-independent differential polarization microscope, which uses polarized light states with the same ellipticity and different orientation angles. Image processing algorithms using three or four frames are described.
TL;DR: In this paper, the experimental estimation of the degree of correlation of statistical vector optical fields must include not only the measurement of the visibility of the interference pattern, but also the deepness of the polarization modulation (degree of polarization) in the resulting spatial distribution of a field.
Abstract: The statement is substantiated that the experimental estimation of the degree of correlation of statistical vector optical fields must include not only the measurement of the visibility of the interference pattern, but also the deepness of the polarization modulation (degree of polarization) in the resulting spatial distribution of a field.
TL;DR: In this article, an ultracompact design of a low-loss silicon polarization rotator based on a silicon-on-insulator platform, which contains an asymmetric strip Si nanowire waveguide core, is presented.
Abstract: In this paper, an ultracompact design of a low-loss silicon (Si) polarization rotator based on a silicon-on-insulator platform, which contains an asymmetric strip Si nanowire waveguide core, is presented. A full-vectorial finite element method and the least squares boundary residual method are used to study the effects of the device parameters, the results of which indicate that a very high polarization conversion with a very low polarization crosstalk is possible.
01 Jan 2011-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this article, a very high level of 3 He polarization of 80.4%±1.5% was obtained and maintained with good time stability with the use of spin exchange optical pumping (SEOP).
Abstract: Maintaining high levels of 3 He polarization over long periods of time is important for many areas of fundamental and particle beam physics. Long measurement times are often required in such experiments, and the data quality is a function of the 3 He polarization. This is the case for neutron scattering, where the 3 He can be used to analyze the spin of a scattered neutron beam. For neutron scattering, the relatively small fluxes of polarized neutrons lead to experiment times longer than several days. Consequently, the Julich Centre for Neutron Science (JCNS) is developing spin-exchange optical pumping (SEOP) systems capable of polarizing the 3 He gas in place on a typical neutron instrument. With the polarizer we have constructed, a very high level of 3 He polarization of 80.4%±1.5% was obtained and maintained with good time stability. Having such high levels of polarization that are stable over time will reduce the measurement times for such experiments and eliminate time-dependent data corrections.
TL;DR: In this paper, the influence of incident light polarization on photonic nanojet using the finite-difference time-domain (FDTD) method is demostrated, and the axial field intensity profiles of both the linear and circular polarization incident beams are very similar.
Abstract: Dielectric microspheres can confine light in a three-dimensional (3D) region called photonic nanojet is shown when they are illuminated by different polarized beams. The influence of incident light polarization on photonic nanojet using the finite-difference time-domain (FDTD) method is demostrated. The axial field intensity profiles of photonic nanojets for both the linear and circular polarization incident beams are very similar. Azimuthal polarization incident beam induces a doughnut beam along the optical axis, while the radial polarization incident beam permits one to reach an effective volume as small as 0.7(\lambda/n)3.
TL;DR: The 3×1 generalized Jones vectors (GJVs) that describe the linear, circular, and elliptical polarization states of an arbitrary three-dimensional (3-D) monochromatic light field are determined in terms of the geometrical parameters of the 3-D vibration of the time-harmonic electric field.
Abstract: The 3×1 generalized Jones vectors (GJVs) [ExEyEz]t (t indicates the transpose) that describe the linear, circular, and elliptical polarization states of an arbitrary three-dimensional (3-D) monochromatic light field are determined in terms of the geometrical parameters of the 3-D vibration of the time-harmonic electric field. In three dimensions, there are as many distinct linear polarization states as there are points on the surface of a hemisphere, and the number of distinct 3-D circular polarization states equals that of all two-dimensional (2-D) polarization states on the Poincare sphere, of which only two are circular states. The subset of 3-D polarization states that results from the superposition of three mutually orthogonal x, y, and z field components of equal amplitude is considered as a function of their relative phases. Interesting contours of equal ellipticity and equal inclination of the normal to the polarization ellipse with respect to the x axis are obtained in 2-D phase space. Finally, the 3×3 generalized Jones calculus, in which elastic scattering (e.g., by a nano-object in the near field) is characterized by the 3-D linear transformation Es=T Ei, is briefly introduced. In such a matrix transformation, Ei and Es are the 3×1 GJVs of the incident and scattered waves and T is the 3×3 generalized Jones matrix of the scatterer at a given frequency and for given directions of incidence and scattering.
Patent•
28 Mar 2011
TL;DR: In this article, a polarization modulator uses two liquid crystal devices arranged in optical series and driven such that the second device compensates a change the first device makes to an input polarization state of incident light during alternate subframes.
Abstract: A polarization modulator for time-multiplexed stereoscopic 3D applications rapidly switches between two polarization states in alternate subframes. The polarization modulator uses two liquid crystal devices arranged in optical series and driven such that the second device compensates a change the first device makes to an input polarization state of incident light during alternate subframes. The compensating liquid crystal devices are characterized in that, if the same voltage is applied to both of them, the second device compensates the change that the first device makes to the input polarization state, regardless of the applied voltage level. If the applied voltage is changed from one level to another and the liquid crystal material in the liquid crystal devices relaxes to the new voltage level, polarization state compensation will take place throughout the duration of the relaxation so that the slow, unpowered transition does not manifest itself as a change in polarization state.