Comparison of linear polarization degree in healthy and wounded rat skin

2001 ◽  
Author(s):  
Martha S. Ribeiro ◽  
Anderson Z. Freitas ◽  
Daniela F. Silva ◽  
Denise M. Zezell ◽  
Cleusa M. R. Pellegrini ◽  
...  
Keyword(s):  
Linear Polarization ◽  
Polarization Degree ◽  
Rat Skin

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.

Polarized emission effect realized in CH3NH3PbI3 perovskite nanocrystals

2017 ◽  
Vol 5 (34) ◽  
pp. 8699-8706 ◽  
Author(s):  
Zhi-Feng Shi ◽  
Ying Li ◽  
Sen Li ◽  
Hui-Fang Ji ◽  
Ling-Zhi Lei ◽  
...  
Keyword(s):  
Linear Polarization ◽  
Polarization Degree ◽  
Perovskite Nanocrystals ◽  
Polarized Emission ◽  
Emission Effect

A polarized emission effect has been realized in CH3NH3PbI3 perovskite nanocrystals with a linear polarization degree of 0.28.

scholarly journals Characterization of mid-infrared polarization due to scattering in protoplanetary disks

2020 ◽  
Vol 634 ◽  
pp. A129 ◽  
Author(s):  
S. Heese ◽  
S. Wolf ◽  
R. Brauer
Keyword(s):  
Magnetic Fields ◽  
Linear Polarization ◽  
Radial Distance ◽  
Protoplanetary Disks ◽  
Field Studies ◽  
Central Star ◽  
Polarization Degree ◽  
Mid Infrared ◽  
Stellar Radiation ◽  
Linearly Polarized

Context. It is generally assumed that magnetic fields play an important role in the formation and evolution of protoplanetary disks. One way of observationally constraining magnetic fields is to measure polarized emission and absorption produced by magnetically aligned elongated dust grains. The fact that radiation also becomes linearly polarized by light scattering at optical to millimeter wavelengths complicates magnetic field studies. Aims. We characterize the linear polarization of mid-infrared radiation due to scattering of the stellar radiation and dust thermal re-emission radiation (self-scattering). Methods. We computed the radial polarization profiles at wavelengths across the N and Q bands for a broad range of circumstellar disk configurations. These simulations served as a basis to analyze the correlations between selected disk parameters and the resulting linear polarization. Results. We find that the thermal re-emission radiation is stronger than the scattered stellar radiation for disks with inner holes smaller than ~10 au within the considered parameter range. The mid-infrared polarization due to scattering shows several clear trends: for scattered stellar radiation only, the linear polarization degree decreases slightly with increasing radial distance, while it increases with radial distance for thermal re-emission radiation only and for a combination of scattered stellar radiation and thermal re-emission radiation. The linear polarization degree decreases with increasing disk flaring and luminosity of the central star. An increasing inner radius shifts the increase of the linear polarization degree further outside, while a larger scale height increases the linear polarization degree for small radial distances and decreases this degree further outside. For longer wavelengths, i.e., toward the Q band in our study, the linear polarization degree converges more slowly. Conclusions. We found several clear trends for polarization due to scattering. These trends are the basis to distinguish polarization due to scattering from polarization due to dichroic emission and absorption.

Anisotropy of the Porous Silicon Photoluminescence

1996 ◽  
Vol 452 ◽  
Author(s):  
G. Polisski ◽  
B. Averboukh ◽  
D. Kovalev ◽  
F. Koch
Keyword(s):  
Porous Silicon ◽  
Memory Effect ◽  
Linear Polarization ◽  
Polarized Light ◽  
Optical Excitation ◽  
Polarization Degree ◽  
Porous Si ◽  
Si Substrate ◽  
Plane Distribution

AbstractPolarization memory effect in the porous Si photoluminescence is studied. The anisotropy of the linear polarization degree is found in the samples etched with polarized light-assistance. The effect is explained by the anisotropie in plane distribution of the elongated Si crystallites. Under resonant optical excitation four-fold anisotropy of the photoluminescence polarization, linked to the crystalline axes of the bulk Si substrate, is observed.

scholarly journals Nanoscopic surface inspection by analyzing the linear polarization degree of the scattered light

2009 ◽  
Vol 34 (12) ◽  
pp. 1906 ◽  
Author(s):  
P. Albella ◽  
J. M. Saiz ◽  
J. M. Sanz ◽  
F. González ◽  
F. Moreno
Keyword(s):  
Linear Polarization ◽  
Scattered Light ◽  
Polarization Degree ◽  
Surface Inspection

scholarly journals Observational indications of magneto-optical effects in the scattering polarization wings of the Ca I 4227 Å line

2020 ◽  
Vol 641 ◽  
pp. A63
Author(s):  
Emilia Capozzi ◽  
Ernest Alsina Ballester ◽  
Luca Belluzzi ◽  
Michele Bianda ◽  
Sajal Kumar Dhara ◽  
...  
Keyword(s):  
Magnetic Fields ◽  
Linear Polarization ◽  
Solar Limb ◽  
Polarization Degree ◽  
Polarization Angle ◽  
Peak Structure ◽  
Line Core ◽  
Optical Effects ◽  
Solar Intensity ◽  
The Magnetic Field

Context. Several strong resonance lines, such as H I Ly-α, Mg II k, Ca II K, and Ca I 4227 Å, are characterized by deep and broad absorption profiles in the solar intensity spectrum. These resonance lines show conspicuous linear scattering polarization signals when observed in quiet regions close to the solar limb. Such signals show a characteristic triplet-peak structure with a sharp peak in the line core and extended wing lobes. The line core peak is sensitive to the presence of magnetic fields through the Hanle effect, which however is known not to operate in the line wings. Recent theoretical studies indicate that, contrary to what was previously believed, the wing linear polarization signals are also sensitive to the magnetic field through magneto-optical (MO) effects. Aims. We search for observational indications of this recently discovered physical mechanism in the scattering polarization wings of the Ca I 4227 Å line. Methods. We performed a series of spectropolarimetric observations of this line using the Zurich IMaging POLarimeter camera at the Gregory-Coudé telescope at Istituto Ricerche Solari Locarno in Switzerland and at the GREGOR telescope in Tenerife (Spain). Results. Spatial variations of the total linear polarization degree and linear polarization angle are clearly appreciable in the wings of the observed line. We provide a detailed discussion of our observational results, showing that the detected variations always take place in regions in which longitudinal magnetic fields are present, thus supporting the theoretical prediction that they are produced by MO effects.

scholarly journals Master equation theory applied to the redistribution of polarized radiation in the weak radiation field limit

2020 ◽  
Vol 644 ◽  
pp. A65
Author(s):  
Véronique Bommier
Keyword(s):  
Linear Polarization ◽  
Computing Time ◽  
Solar Spectrum ◽  
Polarization Degree ◽  
Line Center ◽  
Present Calculation ◽  
Thermodynamical Equilibrium ◽  
Numerical Application ◽  
Instrumental Polarization ◽  
Polarization Profiles

Context. This paper presents a numerical application of a self-consistent theory of partial redistribution in nonlocal thermodynamical equilibrium conditions, developed in previous papers of the series. Aims. The code was described in IV of this series. However, in that previous paper, the numerical results were unrealistic. The present paper presents an approximation able to restore the reliability of the outgoing polarization profiles. Methods. The convergence of the results is also proved. It is demonstrated that the step increment decreases like 1/Nα, with α >  1. Results. Thanks to these additions, the results series behaves like a Riemann series, which is absolutely convergent. However, convergence is not fully reached in line wings within the allocated computing time. Development of efficient acceleration methods would be desirable for future work. Conclusions. Agreement between the computed and observed linear polarization profiles remains qualitative only. The discrepancy is assigned to the plane parallel atmosphere model, which is insufficient to describe the chromosphere, where these lines are formed. As all the integrals are numerical in the code, it could probably be adapted to more realistic and higher dimensional model atmospheres. However, this is time consuming for lines with a hyperfine structure, as in the Na I D lines. The net linear polarization observed in Na I D1 with the Zürich Imaging Polarimeter ZIMPOL mounted on the McMath-Pierce telescope at Kitt Peak is not confirmed by the present calculations and could be an artefact of instrumental polarization. The presence of instrumental polarization could be confirmed by the higher linear polarization degree observed by this instrument in the Na I D2 line center with respect to the present calculation result where the magnetic field is not accounted for. At this precise point, the Hanle effect acts as a depolarizing effect in the second solar spectrum. The observed linear polarization excess is found to be of the same order of magnitude in both line centers, namely 0.1%, which is also comparable to the instrumental polarization compensation level of this experiment.

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