scholarly journals Interstellar Circular Polarization and the Composition of Interstellar Dust

1973 ◽  
Vol 52 ◽  
pp. 161-167 ◽  
Author(s):  
P. G. Martin
Keyword(s):  
Circular Polarization ◽  
Linear Polarization ◽  
Interstellar Dust ◽  
Principal Axis ◽  
Complex Refractive Index ◽  
Polarized Light ◽  
Position Angle ◽  
Optical Observations ◽  
Small Component ◽  
Linearly Polarized

This paper shows that optical observations of circular polarization produced by aligned interstellar grains could yield valuable information about the grain material. The interstellar medium is known to be linearly dichroic from observations of interstellar linear polarization; many different grain models using a large variety of compositions can be found to reproduce these observations. Since the same aligned grains make the medium linearly birefringent, a small component of circular polarization can result from incident linearly polarized light if the position angle of the linear polarization does not coincide with either principal axis of the medium. Here calculations are presented to demonstrate that the wavelength of the circular polarization is sensitive to the imaginary part of the complex refractive index of the grain material. This provides an opportunity of investigating whether the grains are characteristically dielectric or metallic. Some possible observations are suggested.

Elliptically Polarized Natural Modes in Pulsar Magnetospheres

1982 ◽  
Vol 4 (4) ◽  
pp. 365-370 ◽  
Author(s):  
Michelle C. Allen ◽  
D.B. Melrose
Keyword(s):  
Circular Polarization ◽  
Linear Polarization ◽  
Strong Support ◽  
Position Angle ◽  
Average Degree ◽  
Pole Model ◽  
Magnetic Pole ◽  
Pulse Profile ◽  
Linearly Polarized ◽  
High Degree

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).

scholarly journals Neural processing of linearly and circularly polarized light signal in a mantis shrimp Haptosquilla pulchella

2020 ◽  
Vol 223 (22) ◽  
pp. jeb219832
Author(s):  
Tsyr-Huei Chiou ◽  
Ching-Wen Wang
Keyword(s):  
Circular Polarization ◽  
Linear Polarization ◽  
Polarized Light ◽  
Polarization Vision ◽  
Animal Group ◽  
Circularly Polarized Light ◽  
Circularly Polarized ◽  
Mantis Shrimp ◽  
Linearly Polarized ◽  
Vector Angle

ABSTRACTStomatopods, or mantis shrimp, are the only animal group known to possess circular polarization vision along with linear polarization vision. By using the rhabdomere of a distally located photoreceptor as a wave retarder, the eyes of mantis shrimp are able to convert circularly polarized light into linearly polarized light. As a result, their circular polarization vision is based on the linearly polarized light-sensitive photoreceptors commonly found in many arthropods. To investigate how linearly and circularly polarized light signals might be processed, we presented a dynamic polarized light stimulus while recording from photoreceptors or lamina neurons in intact mantis shrimp Haptosquilla pulchella. The results indicate that all the circularly polarized light-sensitive photoreceptors also showed differential responses to the changing e-vector angle of linearly polarized light. When stimulated with linearly polarized light of varying e-vector angle, most photoreceptors produced a concordant sinusoidal response. In contrast, some lamina neurons doubled the response frequency in reacting to linearly polarized light. These responses resembled a rectified sum of two-channel linear polarization-sensitive photoreceptors, indicating that polarization visual signals are processed at or before the first optic lobe. Noticeably, within the lamina, there was one type of neuron that showed a steady depolarization response to all stimuli except right-handed circularly polarized light. Together, our findings suggest that, between the photoreceptors and lamina neurons, linearly and circularly polarized light may be processed in parallel and differently from one another.

Split and Merge of Left–Right Circular Polarized Light through Coupled Magnetic Resonators

2012 ◽  
Vol 67 (8-9) ◽  
pp. 491-497
Author(s):  
Jijun Wang ◽  
Jing Cao ◽  
Min Zhu ◽  
Zhipan Zhu ◽  
Yun-tuan Fang
Keyword(s):  
Circular Polarization ◽  
Linear Polarization ◽  
Transfer Matrix Method ◽  
Polarized Light ◽  
Light Polarization ◽  
Transmission Properties ◽  
Left Handed ◽  
Linearly Polarized ◽  
Split And Merge ◽  
Control Light

In order to obtain the means to control light polarization, we designed a structure of coupled magnetic resonators and studied its transmission properties by the 4x4 transfer matrix method. The incidence of linearly polarized light results in two transmission resonant peaks of left-handed circular polarization at shorter wavelengths and two transmission resonant peaks of right-handed circular polarization at longer wavelengths, respectively. Through adjusting the magnetizations, the inner left-handed circular polarization and right-handed circular polarization can be merged into one linear polarization, while the two outside resonant peaks keep their circular polarization. The polarized direction of the output linearly polarized light can be controlled by the polarized direction of incidence light. The incidence light with one polarization can output light with three kinds of polarizations through the designed structure.

scholarly journals Polarization perception in humans: on the origin of and relationship between Maxwell’s spot and Haidinger’s brushes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Gary P. Misson ◽  
Shelby E. Temple ◽  
Stephen J. Anderson
Keyword(s):  
Linear Polarization ◽  
Light Absorption ◽  
Polarized Light ◽  
Retinal Images ◽  
Clinical Use ◽  
Differential Absorption ◽  
Model Simulations ◽  
Eye Disorders ◽  
Absorption Of Light ◽  
Linearly Polarized

AbstractUnder specific conditions of illumination and polarization, differential absorption of light by macular pigments is perceived as the entoptic phenomena of Maxwell’s spot (MS) or Haidinger’s brushes (HB). To simulate MS and HB, an existing computational model of polarization-dependent properties of the human macula was extended by incorporating neuronal adaptation to stabilized retinal images. The model predicted that polarized light modifies the appearance of MS leading to the perception of a novel phenomenon. The model also predicted a correlation between the observed diameters of MS and HB. Predictions were tested psychophysically in human observers, whose measured differences in the diameters of each entoptic phenomenon generated with depolarized and linearly polarized light were consistent with the model simulations. These findings support a common origin of each phenomenon, and are relevant to the clinical use of polarization stimuli in detecting and monitoring human eye disorders, including macular degeneration. We conclude: (i) MS and HB both result from differential light absorption through a radial diattenuator, compatible with the arrangement of macular pigments in Henle fibres; (ii) the morphology of MS is dependent on the degree of linear polarization; (iii) perceptual differences between MS and HB result from different states of neural adaptation.

scholarly journals Simultaneous Five Color (UBVRI) Polarimetry of VV Puppis

1987 ◽  
Vol 93 ◽  
pp. 203-203
Author(s):  
V. Piirola ◽  
A. Reiz ◽  
G.V. Coyne
Keyword(s):  
Circular Polarization ◽  
Linear Polarization ◽  
Wavelength Dependence ◽  
Position Angle ◽  
Orbital Inclination ◽  
V Band ◽  
Highly Active ◽  
Phase Interval ◽  
In The Beginning ◽  
Bright Phase

AbstractObservations of linear and circular polarization in five colour bands during a highly active state of VV Puppis in January 86 are reported. A strong linear polarization pulse with the maximum in the blue, PB ≈ 22%, is observed at the end of the bright phase when the active pole is at the limb and a weaker secondary pulse, PB ≈ 7%, is seen in the beginning of the bright phase, when the active pole reappears. Strong positive circular polarization is also observed in the blue and the ultraviolet, РU ≈ PB ≈ 18%, PV ≈ 10% during the bright phase. The circular polarization reverses the sign in the B and V bands during the faint phase and a negative polarization hump is seen when the active pole crosses the limb. The circular polarization in the V band reaches the value PV ≈ −10% at the hump, after which it remains near PV ≈ −5% during the faint phase. This is probably due to radiation coming from the second, less active pole and accretion thus takes place onto both poles. The wavelength dependences of the positive and negative parts of the circular polarization curve are different and no polarization reversal is seen in the U band. The position angle of the linear polarization is well determined during a large portion of the cycle, especially in the V band, thanks to the activity from both poles. A best fit to the position angle curve, taking into account also the duration of the positive circular polarization phase interval ΔΦ = 0.40 (in the V band), yields the values of orbital inclination i = 78° ± 2° and the colatitude of the active magnetic pole ß = 146° ± 2°. The relatively good fit to the position angle data indicates that the simple dipole model is nearly correct in the case of VV Puppis. Some wavelength dependence is, however, seen in the position angle curves, especially in the I band where the slope Δθ/ΔΦ at the main pulse is considerably smaller than in the other bands. The shape of the position angle curves changes also in the blue and the ultraviolet around the middle of the bright phase. This is probably due to optical thickness effects as the side of the accretion column which is toward the observer changes near this phase.

Design of multiband circularly/linearly polarized antenna for multiple wireless (WWAN/Bluetooth/WiMAX/WLAN/Downlink Satellite System)

2019 ◽  
Vol 11 (9) ◽  
pp. 967-974 ◽  
Author(s):  
Manish Sharma
Keyword(s):  
Wireless Communications ◽  
Circular Polarization ◽  
Radiation Pattern ◽  
Linear Polarization ◽  
Ground Plane ◽  
Wireless Systems ◽  
Satellite System ◽  
Multiband Antenna ◽  
Linearly Polarized ◽  
Downlink System

AbstractIn this article, a multiband antenna for various wireless communications is proposed for WWAN, Bluetooth, WiMAX, WLAN, and Downlink satellite system. The antenna consists of a radiating patch and a rectangular ground plane with four L-shaped stubs which are embedded as side arms to obtain a resonating band for WWAN (1.9GHz), Bluetooth (2.4 GHz), WiMAX (2.5, 3.5, and 5.5 GHz), and WLAN (5.5 GHz) wireless systems and a C-shaped stub is etched on the radiating patch to obtain a higher WLAN band (2.4, 5.2, and 5.8 GHz) and a satellite downlink system (7.5 GHz). The proposed antenna exhibits circular polarization at WWAN band and linear polarization for remaining applications. Also, the proposed antenna exhibits an omnidirectional radiation pattern.

scholarly journals Polarization in Pulsar Radio Emission

1992 ◽  
Vol 128 ◽  
pp. 384-386
Author(s):  
D. M. GOULD
Keyword(s):  
Radio Emission ◽  
Circular Polarization ◽  
Linear Polarization ◽  
Large Data ◽  
Position Angle ◽  
Published Data ◽  
Data Set ◽  
Pulsar Radio ◽  
Polarization Profiles ◽  
Pulsar Radio Emission

Polarimetric observations of over 300 pulsars have been carried out between 21 December 1988 and 22 January 1990 at 606, 610, 925, and 1408 MHz using the Lovell Telescope at Jodrell Bank. Many of these pulsars have no previously published polarization profiles and will be published shortly (Gould and Lyne 1990). This large data set along with previously published data from various sources, has been used to test the correlation found by Radhakrishnan and Rankin (1990) between sense reversing circular polarization signatures and the accompanying sense of rotation of the linear polarization position angle.

scholarly journals Polarization Variability of Some Compact Radio Sources

1982 ◽  
Vol 97 ◽  
pp. 331-333
Author(s):  
M. M. Komesaroff ◽  
D. K. Milne ◽  
P. T. Rayner ◽  
J. A. Roberts ◽  
D. J. Cooke
Keyword(s):  
Circular Polarization ◽  
Linear Polarization ◽  
Position Angle ◽  
Linear Increase ◽  
Monitoring Programme ◽  
Radio Sources ◽  
List Type ◽  
Type Number ◽  
5 Ghz ◽  
Superluminal Expansion

Figure 1 shows observations for four sample sources from the Parkes 5 GHz polarization monitoring programme. Interesting features illustrated include •Sudden changes of the position angle of the linear polarization by ≳ 70° in PKS 0537-441 and 1253-055 (3C279).•A linear increase in the position angle of the polarization of PKS 2134+004 through 70° over 3/12; years.•Distinct bursts of circular polarization in PKS 0430+052, 0537-441 and 1253-055. In PKS 0430+052 (3C120) such a burst coincides with the possible superluminal expansion (Walker et al., 1981). In PKS 1253-055 (3C279) a burst of circular polarization is currently occurring at a time of very low linear polarization.

3mm POLARIZATION PROPERTIES OF OPTICAL AND γ-RAY CLASSES OF BLAZARS

2010 ◽  
Vol 19 (06) ◽  
pp. 923-929
Author(s):  
I. AGUDO ◽  
C. THUM ◽  
H. WIESEMEYER ◽  
T. P. KRICHBAUM
Keyword(s):  
Linear Polarization ◽  
Position Angle ◽  
Polarization Degree ◽  
Polarization Angle ◽  
Marginal Effect ◽  
Bl Lacertae ◽  
All Optical ◽  
Linearly Polarized ◽  
Γ Ray ◽  
The One

We have performed the first 3.5 mm polarimetric survey of radio loud active galactic nuclei (AGN) with the IRAM 30 m Telescope. Unlike radio wavelengths, millimeter observations allow us to measure the intrinsic linearly polarized emission from AGN, thanks to the marginal effect of Faraday rotation and depolarization at mm wavelengths. The sample contains 145 sources, and it essentially consists of all flat-spectrum AGN with declinations accessible to the 30 m Telescope (Dec. ( J 2000.0) > -30°), and with 3 mm flux density ≳ 1 Jy, as measured from 1978 to 1994. LBAS quasars in our sample show larger luminosity than non-LBAS ones, which is consistent with previous work claiming larger Doppler factors for brighter γ-ray blazars. This effect cannot be claimed for BL Lacertae objects in our sample, which suggests that only quasars contribute to distribute LBAS blazars towards larger luminosities. We find a systematic 3.5 mm linear polarization degree excess by a factor of ~ 2 with regard to the one at 2 cm for all optical and γ-ray classes of sources considered here. Our sample shows a significant trend to increase the luminosity of their jets for decreasing linear polarization fraction. Unlike previous studies in the radio spectral range, we do not find a clear relation between the linear polarization angle and the jet structural position angle of any source class in our sample. This is interpreted as a markedly non-axisymmetric character of the 3 mm emitting region of radio loud AGN jets.

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