Showing papers on "Optical polarization published in 2001"
TL;DR: In this paper, the authors consider a class of beams that are both partially polarized and partially coherent from the spatial viewpoint, characterized by a correlation matrix whose elements have the same form as the mutual intensity of a Gaussian Schell-model beam.
Abstract: We consider a class of beams that are both partially polarized and partially coherent from the spatial standpoint. They are characterized by a correlation matrix whose elements have the same form as the mutual intensity of a Gaussian Schell-model beam. We focus our attention on those beams that would appear identical to ordinary Gaussian Schell-model beams in a scalar treatment. After establishing some inequalities that limit the choice of the matrix parameters, we study the main effects of propagation. Starting from the source plane, in which the beam is assumed to be uniformly polarized, we find that in the course of propagation the degree of polarization generally becomes non-uniform across a typical section of the beam. Furthermore, we find that the intensity distribution at the output of an arbitrarily oriented linear polarizer is Gaussian shaped at the source plane whereas it can be quite different at other planes.
244 citations
TL;DR: In this article, a model based on the pupil approach and the Fourier modal method is presented for numerical simulation of high numerical aperture polarization microscopy images and the near-fields producing them.
160 citations
TL;DR: In this paper, it was shown that by impinging radial polarization on a solid immersion lens (SIL) system, a rotational symmetric z-component of the focused wavefront with spot size similar to that predicted by scalar theory can be obtained.
153 citations
TL;DR: The template-directed dye-terminator incorporation assay with fluorescence polarization detection (FP-TDI), which uses four spectrally distinct dye terminators to achieve universal assay conditions, can be used for assaying any SNP marker and greatly simplifies the SNP genotyping assay design.
Abstract: The degree of fluorescence polarizatio n (FP) of a fluorescent molecule is a refle c tion of its molecular weight ( M r ). FP i s therefore a useful detection method for h o mogeneous assays in which the startin g reagents and products differ significantly i n M r . We have previously shown that FP is a good detection method for the single-bas e extension and the 5 ′-nuclease assays. In thi s report, we describe a universal, optimize d single-base extension assay for genotypin g single nucleotide polymorphisms (SNPs) . This assay, which we named the template directed dye-terminator incorporation a s say with fluorescence polarization detectio n (FP-TDI), uses four spectrally distinct dy e terminators to achieve universal assay co n ditions. Even without optimization, approx i mately 70% of all SNP markers tested yiel d ed robust assays. The addition of an E. col i ssDNA-binding protein just before the FP reading significantly increased FP values o f the products and brought the success rate o f FP-TDI assays up to 90%. Increasing th e amount of dye terminators and reducing th e number of thermal cycles in the single-bas e extension step of the assay increased th e separation of the FP values between th e products corresponding to different gen o types and improved the success rate of th e assay to 100%. In this study, the genomi c DNA samples of 90 individuals were type d for a total of 38 FP-TDI assays (using bot h the sense and antisense TDI primers for 1 9 SNP markers). With the previously d e scribed modifications, the FP-TDI assa y gave unambiguous genotyping data for al l the samples tested in the 38 FP-TDI assays . When the genotypes determined by the FP TDI and 5 ′-nuclease assays were compared , they were in 100% concordance for all e x periments (a total of 3420 genotypes). Th e four-dye-terminator master mixture d e scribed here can be used for assaying an y SNP marker and greatly simplifies the SNP genotyping assay design .
125 citations
TL;DR: In this paper, the transmission and Faraday rotation characteristics of one-dimensional photonic crystals in cerium-substituted yttrium iron garnet (Ce:YIG) with multiple defects in the optical bandgap were studied theoretically at /spl lambda/ = 1.55 /spl mu/m.
Abstract: The transmission and Faraday rotation characteristics of one-dimensional photonic crystals in cerium-substituted yttrium iron garnet (Ce:YIG) with multiple defects in the optical bandgap are studied theoretically at /spl lambda/ = 1.55 /spl mu/m. It is found that the interdefect spacing can be adjusted to yield a flat top response, with close to 100% transmission and 45/spl deg/ Faraday rotation, for film structures as thin as 30 to 35 /spl mu/m. This is better than a three-fold reduction in thickness compared to the best Ce:YIG films for comparable rotations, and may allow a considerable reduction in size in manufactured optical isolators. Transmission bands as wide as 7 nm are predicted, which constitutes a considerable improvement over previously reported bandwidths for magnetic photonic crystals. Diffraction across the structure corresponds to a longer optical path length than the thickness of the film, calling for the use of guided optics to minimize insertion losses in integrated devices. The basis for the flat-top transmission in ferrite photonic crystals is presented and discussed.
124 citations
TL;DR: Optical polarization of 3 He generates large nuclear spin magnetizations, allowing MR imaging of the gas spaces of human and animal lungs despite the low number of spins in the gas as mentioned in this paper.
Abstract: Optical polarization of 3 He generates large nuclear spin magnetizations, allowing MR imaging ofthe gas spaces ofhuman and animal lungs despite the low number den- sity ofspins in the gas. The atomic physics ofoptical pumping and spin exchange is explained; the hardware for polarizing, transporting, and imaging is detailed. Pulse sequences for optimum use of the nonrenewable magnetization require a different imaging strategy than traditional proton MRI. Examples are discussed for static lung images, diffusion images for characteriza- tion ofthe local alveolar structure, and high temporal resolution images. © 2001 John Wiley &
115 citations
TL;DR: In this paper, the degree of polarization (DOP) degradation of optical signal induced by polarization mode dispersion (PMD) in high-speed optical fiber transmission is investigated in detail.
Abstract: The basic property of degree of polarization (DOP) degradation of optical signal induced by polarization mode dispersion (PMD) in high-speed optical fiber transmission is investigated in detail. The DOP of the optical signal reflects the degree of waveform degradation caused by PMD, therefore, it is proposed to be used as the control signal judging the best compensation point for the optical adaptive PMD compensation techniques. However, the signal DOP is not only affected by PMD, but also by various factors, such as the modulation format, modulator chirp, fiber nonlinearity, amplified spontaneous emission (ASE), and so on. We use numerical simulations and experiments to explore the basic DOP property to detect PMD with these factors. We also show that using the signal DOP as control signal is especially useful for the optical duo-binary modulation because of its high sensitivity and wide PMD detection range.
114 citations
TL;DR: In this article, an additional equation for material polarization in the well-known traveling wave model was introduced to investigate the polarization-induced changes in the spectral properties of the optical waveguide and showed the relevance of this model for a more realistic simulation of the complicated dynamical behavior of multi-section distributed feedback (DFB) lasers.
Abstract: We present a refined model for multi-section lasers, introducing an additional equation for material polarization in the well-known traveling wave model. We investigate the polarization-induced changes in the spectral properties of the optical waveguide. Finally, we show the relevance of this model for a more realistic simulation of the complicated dynamical behavior of multi-section distributed feedback (DFB) lasers, such as fast self-pulsations, multi-stability, and hysteresis effects due to mode competition.
94 citations
TL;DR: In this article, the probability density function (pdf) of the differential group delay (DGD) is derived for fiber communication systems limited by polarization-mode dispersion (PMD) using statistics.
Abstract: Fiber communication systems limited by polarization-mode dispersion (PMD) are usually analyzed using statistics. The probability density function (pdf) of the differential group delay (DGD) is then crucial to know. There are cases for which the commonly used Maxwellian pdf is only approximate, e.g., PMD emulators, or systems with components having single components with large deterministic PMD. Those cases are discussed in this paper, and their pdfs are derived. To do this, we present a very general theory that allows for the derivation of the pdf for almost any birefringent transmission line. As a side result, we are able to prove that the square-sum concatenation formula is valid in almost every case of interest, even if the pdf is far from Maxwellian.
93 citations
TL;DR: In this article, the results of generalized measurements of optical polarization designed to provide one of three or four distinct outcomes were presented, which allowed them to discriminate between nonorthogonal polarization states with an error probability that is close to the minimum allowed by quantum theory.
Abstract: We present the results of generalized measurements of optical polarization designed to provide one of three or four distinct outcomes. This has allowed us to discriminate between nonorthogonal polarization states with an error probability that is close to the minimum allowed by quantum theory. Employing these optimal detection strategies on sets of three (trine) or four (tetrad) equiprobable symmetric nonorthogonal polarization states, we obtain a mutual information that exceeds the maximum value attainable using conventional (von Neumann) polarization measurements.
79 citations
TL;DR: In this article, the authors analyzed polarization mode dispersion (PMD) emulators comprised of a small number of sections of polarization-maintaining fibers with polarization scattering at the beginning of each section.
Abstract: We analyze polarization mode dispersion (PMD) emulators comprised of a small number of sections of polarization-maintaining fibers with polarization scattering at the beginning of each section. Unlike previously studied devices, these emulators allow the emulation of a whole ensemble of fibers. We derive an analytical expressions and determine two main criteria that characterize the quality of PMD emulation. The experimental results are in good agreement with the theoretical predictions.
TL;DR: The results show that the blood-compatibility of composite membranes with the concentration of liquid crystal 20, 30% (wt) is more excellent than that of other composite membranes.
TL;DR: Vibrational sum frequency generation (SFG) spectroscopy has been developed to a stage of surface sensitivity that is comparable to the classical surface science methods and has been successfully employed to study a variety of adsorbate-substrate interfaces and due to its surface-specificity it allows the study of ads absorbates from submonolayer coverages up to atmospheric gas pressure as mentioned in this paper.
Abstract: Vibrational sum frequency generation (SFG) spectroscopy has been developed to a stage of surface sensitivity that is comparable to the classical surface science methods. SFG has been successfully employed to study a variety of adsorbate–substrate interfaces and due to its surface-specificity it allows the study of adsorbates from submonolayer coverages up to atmospheric gas pressure. A number of case studies is presented including adsorption, co-adsorption and reactions on single crystal surfaces and supported nanoparticles. Studies of CO adsorption on Pt(111) and Pd(111) from 10−7 to 1000 mbar have shown that the high pressure adsorbate structures were comparable with saturation structures obtained at low temperature in ultrahigh vacuum. No evidence for pressure-induced surface rearrangements was found. However, pronounced differences in the CO adsorbate structure on supported Pd nanoparticles and on Pd(111) were detected. It
is further shown how polarization dependent SFG can be employed to determine molecular orientations of CO and NO and how SFG is carried out during ethylene hydrogenation. Broadband techniques allow the performance of time-resolved pump–probe SFG experiments and to take “snapshots” of the transient vibrational spectrum.
TL;DR: In this paper, the infrared intersubband optical transitions in SiGe/Si quantum wells were theoretically examined and it was shown that the p-p interaction favors inter-band transitions for an optical polarization parallel to the layer plane.
Abstract: The infrared intersubband optical transitions in SiGe/Si quantum wells is theoretically examined. We have used the $8\ifmmode\times\else\texttimes\fi{}8,$ $12\ifmmode\times\else\texttimes\fi{}12,$ and $14\ifmmode\times\else\texttimes\fi{}14$ $\mathbf{k}\ensuremath{\cdot}\mathbf{p}$ Hamiltonians taking into account both the p-like first conduction band and the s-like second conduction band to calculate wave functions and energy dispersion of the valence band of ${\mathrm{S}\mathrm{i}/\mathrm{S}\mathrm{i}}_{0.8}{\mathrm{Ge}}_{0.2}/\mathrm{Si}$ quantum wells. We discuss intersubband absorption in the valence band and we show that the p-p interaction favors intersubband transitions for an optical polarization parallel to the layer plane $(x$ polarization). For z polarization, both s-p and p-p interactions play the same footing role in intervalence band transitions.
TL;DR: In this article, the design of a single-section polarization splitter in a deeply etched semiconductor MMI waveguide is presented, which can yield more than 8dB polarization separation and only 0.11dB optical loss.
Abstract: The design of a single-section polarization splitter in a deeply etched semiconductor MMI waveguide is presented. Numerically simulated results indicate that the semiconductor MMI exhibits considerable polarization dependence and, utilizing this effect, a compact 1.6-mm-long polarization splitter may be fabricated to yield more than 8-dB polarization separation and only 0.11-dB optical loss, using a very simple design-approach.
TL;DR: In this article, a broad-band polarimetry for near-infrared color-selected AGN classified QSOs based on their K-band luminosity is presented, which is consistent with the idea that the orientation of AGN to the line of sight plays a major role in determining their observed properties.
Abstract: Optical broad-band polarimetry is presented for near-infrared color-selected AGN classified QSOs based on their K-band luminosity. More than 10% of a sample of 70 QSOs discovered in the Two Micron All Sky Survey (2MASS) with J-K > 2 and M_K 3%), and values range to a maximum of P = 11%. High polarization tends to be associated with the most luminous objects at K, and with QSOs having the highest near-IR-to-optical flux ratios. The 2MASS QSO sample includes objects possessing a wide range of optical spectral types. High polarization is seen in two of 22 broad emission-line (Type 1) objects, but 1/4 of the QSOs of intermediate spectral type (Type 1.5-1.9) are highly polarized. None of the nine QSOs classified as Type 2 exhibit P > 3%. It is likely that the unavoidable inclusion of unpolarized starlight from the host galaxy within the observation aperture results in reduced polarization for the narrow emission-line objects. The high polarization of 2MASS-discovered QSOs supports the conclusion inferred from their near-IR and optical colors, that the nuclei of many of these objects are obscured to some degree by dust. The 2MASS QSO sample is compared to other, predominantly radio-quiet, QSOs and is found to be consistent with the idea that the orientation of AGN to the line of sight plays a major role in determining their observed properties.
TL;DR: In this paper, a phase memory time of $3.6 \ensuremath{\mu}\mathrm{s} was measured, and coupling of the electronic spin to the nuclear spin was observed.
Abstract: Electron spin echoes were performed on nitrogen-vacancy $(\mathrm{N}\ensuremath{-}V)$ centers in diamond using optical polarization and detection and 35 GHz microwave control. The experiments demonstrate an approach to quantum information in the solid state. A phase memory time of $3.6 \ensuremath{\mu}\mathrm{s}$ was measured, and coupling of the electronic spin to the ${}^{14}\mathrm{N}$ nuclear spin was observed. Because of the favorable properties of the $\mathrm{N}\ensuremath{-}V$ center, interesting extensions of these single-qubit operations can be proposed.
TL;DR: In this paper, the second-order polarization mode dispersion (PMD) components associated with depolarization of the principal states can cause significant system impairments and the probability densities of these components are discussed.
Abstract: The second-order polarization mode dispersion (PMD) components associated with depolarization of the principal states can cause significant system impairments. We discuss the probability densities of these components and find excellent agreement between extensive measurements, simulations, and theoretical predictions.
TL;DR: The results suggest that nonspecific interactions exist between xenon and the protein exteriors and the data are analyzed in term of parameters which characterize the protein surfaces.
TL;DR: In this article, the authors describe how to evaluate exactly in a recursive manner the Jones transfer matrix of a fiber for any order of polarization mode dispersion and derive for it a second-order accurate analytical approximation.
Abstract: Describes how to evaluate exactly in a recursive manner the Jones transfer matrix of a fiber for any order of polarization mode dispersion (PMD) and derives for it a second-order accurate analytical approximation. The second-order approximation is then compared against the exact result as well as with other models found in the literature.
TL;DR: In this paper, the polarizability anisotropy of liquid-crystalline 4'-pentyloxy-4-cyanobiphenyl (OCB) was calculated for both Vuks and Neugebauer local field models.
Abstract: Various methods of order parameter determination from optical measurements are compared. Measurement results of birefringence and refractive index of liquid-crystalline 4'-pentyloxy-4-cyanobiphenyl (OCB) in the nematic phase are reported. Using these data, the polarizability anisotropy was calculated for both Vuks and Neugebauer local field models. Polarizabilities calculated in this way were applied to determine /spl Delta//spl alpha/ (polarizability anisotropy in the case of perfect orientation) using either Haller's or Subramhanyam's normalization procedures. These procedures enabled the calculation of the orientation order parameter. Polarizabilities calculated using both local field models and both normalization procedures have been compared. The values of polarizability anisotropy for both local electric field models differ significantly (/spl les/30%). No criterion is known to decide which value is correct. To avoid the determination of uncertain /spl alpha//sub i/ and /spl Delta//spl alpha/ values, a simple procedure was used for evaluation of S, based solely on birefringence measurement. This procedure gave very reasonable results.
Patent•
03 Aug 2001
TL;DR: In this paper, a single optical fiber is wrapped around each tube in a cascade of separate piezoelectric tubes, with random amounts of fixed birefringence separating each tube, where each tube is then separately excited on a time-varying basis.
Abstract: Apparatus and an accompanying method for an optical scrambler and particularly one that provides randomly scrambled states of polarization (SOPs) in an optical fiber. Specifically, polarization independence is achieved by wrapping a single optical fiber around each tube in a cascade of separate piezoelectric tubes, with random amounts of fixed birefringence separating each tube, where each tube is then separately excited on a time-varying basis. The tubes are arranged in two groups. Each tube in the first group is separately excited by combined frequency/amplitude modulation with illustratively different modulating frequencies and amplitudes, and in the second group is excited at illustratively a constant frequency and voltage. Time-varying birefringence produced by each tube perturbs an initial SOP of the light provided by that tube from its original pseudo-stationary position as depicted on a poincare sphere.
TL;DR: In this paper, a traveling-wave photodetector (TW-PD) was used for optical heterodyne millimeter-wave generation in excess of 160 GHz in the frequency domain and the maximum electrical power delivered by the TW-PD to a 5052 impedance is -11.5 dBm at 110 GHz with a polarization penalty of only 1.3 dB.
Abstract: Optical heterodyne millimeter-wave generation using traveling-wave photodetectors (TW-PDs) is examined both experimentally and theoretically. Ultrahigh-frequency InP-based 1.55-/spl mu/m TW-PDs were fabricated and employed in an experimental setup for optical heterodyning. For the first time, optical heterodyne millimeter-wave generation in excess of 160 GHz is experimentally demonstrated in the frequency domain. The maximum electrical power delivered by the TW-PD to a 5052 impedance is -11.5 dBm at 110 GHz with a polarization penalty of only 1.3 dB. Furthermore, a theoretical analysis in frequency domain is presented describing the frequency response of TW-PD including effects of the photogenerated carrier dynamics as well as optical and electrical wave propagation phenomena. A broadband and flat frequency response is found indicating a total rolloff of about 13.1 dB for a frequency span from 25 GHz to 200 GHz. Finally, the detectors responsivity is theoretically investigated to differentiate between the physical phenomena associated with high-frequency limitations.
TL;DR: In this article, the vector vortex of the first order appears as zero and pole of the complex homographic function w = (X + iY)(1-Z)-1.
Abstract: New approaches to the characterization of the vector vortical structure of the paraxial monochromatic field are introduced using the analogy between vector field singularities in a distribution of the unit vector of normalized Stokes parameters m(X,Y,Z),m2 = 1 in the transverse plane and topological solitons in a 2D ferromagnet. In this approach the vector vortex of the first order appears as zero and pole of the complex homographic function w = (X + iY)(1-Z)-1. The application of the developed method to the results of numerical simulations of a large aperture Zeeman laser is presented.
TL;DR: In this article, the PMD and PDL for a short pulse can be very different from those for a narrow-band pulse in optical fibers, and it is shown that the effective PMD can be either larger than the sum of the differential group delays (DGDs) of two fibers or less than the DGD difference of the two fibers, depending on the input pulsewidth.
Abstract: Polarization mode dispersion (PMD) and polarization dependent loss (PDL) for a pulse in optical fibers are calculated with a model of two concatenated fibers. Each of the two fibers has both elliptical birefringence and PDL. The results show that the PMD and PDL for a short pulse can be very different from those for a narrow-band pulse in optical fibers. Two anomalous results are reported: (1) the effective PDL for a pulse can be smaller than the PDL difference of the two fibers and (2) the effective PMD for a pulse can be either larger than the sum of the differential group delays (DGDs) of the two fibers or less than the DGD difference of the two fibers, depending on the input pulsewidth. The pulse distortions when the pulses are launched into the two principal states of polarization (PSPs) are discussed.
TL;DR: Optical polarization of seven selected BL Lac objects in UBVRI bands was studied with the Nordic Optical Telescope from December 10{14] 1999 as mentioned in this paper. But the results are discussed within the standard model for BL Lacs.
Abstract: Optical polarization of seven selected BL Lac objects in UBVRI bands was studied with the Nordic Optical Telescope from December 10{14, 1999. Two of them, 3C 66A and PKS 0735+178, were monitored for 4 nights for a total integration time of 4.75 and 5.5 hours, respectively. Other objects (1 Jy 0138 097, H 0414+009, PKS 0823 223, OJ287 and BL Lac) were observed sparsely during the run. Apart from PKS 0823 223 (more polarized than observed in the past), the sources show levels of flux and polarization consistent with results at previous epochs. 3C 66A and PKS 0735+178 were intensively observed during December 11 and 12 and exhibited variability of polarization, both on internight and intranight time scales. Wavelength dependence of polarization has been investigated, as well as circular polarization. The results are discussed within the standard model for BL Lacs.
TL;DR: An approach based on a combination of generalized polarization gratings and diffractive axicons is introduced for transforming an electromagnetic plane wave into a conical wave that exhibits the property of approximate propagation invariance.
TL;DR: In this article, the authors carried out polarization measurements on a two-photon quantum state generated by spontaneous parametric down conversion and showed that the state is unpolarized in the classical theory, but it is not invariant under geometric rotation.
TL;DR: In this paper, a method and a device are proposed that allow measurement of the polarization mode dispersion (PMD) in a transmission line without data traffic interruption, where the PMD vector information is extracted from the optical data signal spectrum.
Abstract: A method and a device are proposed that allow measurement of the polarization mode dispersion (PMD) in a transmission line without data traffic interruption. The PMD vector information is extracted from the optical data signal spectrum. The method is experimentally verified by measuring of first-order PMD.
TL;DR: In this paper, the authors reported the discovery of a bright quasar (E = 15.8, z = 0.868) associated with the flat-spectrum radio source NVSS J235953-124148.
Abstract: We report the discovery of a bright quasar (E = 15.8, z = 0.868) associated with the flat-spectrum radio source NVSS J235953-124148. This quasar, which we designate QSO 2359-1241, possesses a rare combination of extreme properties that make it of special interest. These properties include intrinsic high-velocity outflow seen in absorption for both high- and low-ionization species, high optical polarization (~5%), significant radio emission, and dust reddening. The dereddened absolute magnitude of QSO 2359-1241 places it among the three most optically luminous quasars known at z < 1. High-resolution spectroscopy and a detailed analysis of the optical/ultraviolet absorption features will be given in a companion paper.