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

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 Linear spectropolarimetry: a new tool for the physical characterization of asteroids

2014 ◽  
Vol 10 (S305) ◽  
pp. 319-324
Author(s):  
S. Bagnulo ◽  
A. Cellino ◽  
M. F. Sterzik
Keyword(s):  
Remote Sensing ◽  
Solar System ◽  
Linear Polarization ◽  
Scattered Light ◽  
Wavelength Dependence ◽  
Reflectance Spectra ◽  
The Moon ◽  
Polarization Spectra ◽  
Reflectance Measurements

AbstractThe surfaces of the atmosphere-less objects of our solar system are traditionally probed via reflectance measurements and/or broadband linear polarimetry. Little attention has been paid so far to the wavelength dependence of the linear polarization of the scattered light. We decided to explore the potential of spectropolarimetry as a remote sensing tool for asteroids in addition to the more traditional reflectance measurements, and we carried out a spectropolarimetric survey of asteroids – to our best knolwedge, the first of its kind. We observed a sample of asteroids of different albedo and taxonomic classes, as well as a few regions at the limb of the Moon. We show that objects exhibiting similar reflectance spectra may display totally different polarization spectra, and we suggest that both intensity and polarization spectra should be used for asteroid classification. We also found that in some cases the Umov law is violated, that is, in contrast to what is expected from simple physical considerations, the fraction of linear polarization and the reflectance spectra may be correlated positively. We conclude that future modelling attempts of the surface structure of asteroids should be aimed at explaining both reflectance and polarization spectra.

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.

scholarly journals Near-infrared polarimetric study of near-Earth object 252P/LINEAR: an implication of scattered light from the evolved dust particles

2019 ◽  
Vol 629 ◽  
pp. A121 ◽  
Author(s):  
Yuna G. Kwon ◽  
Masateru Ishiguro ◽  
Jungmi Kwon ◽  
Daisuke Kuroda ◽  
Myungshin Im ◽  
...  
Keyword(s):  
Heliocentric Distance ◽  
Near Infrared ◽  
Scattered Light ◽  
Polarization Vector ◽  
Close Approach ◽  
Dust Particles ◽  
Polarization Degree ◽  
Dynamical Simulation ◽  
The Earth ◽  
Rare Opportunity

Context. Comets undergo resurfacing due to solar radiation, while their primordial interiors remain unchanged. Multi-epoch observations of comets enable us to characterize a change in sublimation pattern as a function of heliocentric distance, which in turn provides information on the dust environments of comets. Aims. We aim to constrain the size and porosity of ejected dust particles from comet 252P/LINEAR and their evolution near perihelion via near-infrared (NIR) multiband polarimetry. A close approach of the comet to the Earth in March 2016 (~0.036 au) provided a rare opportunity for the sampling of the comet at high spatial resolution. Methods. We made NIR JHKS-band (1.25–2.25 μm) polarimetric observations of the comet for 12 days near perihelion, interspersed between broadband optical (0.48–0.80 μm) imaging observations over four months. In addition, a dynamical simulation of the comet was performed 1000 yr backward in time. Results. We detected two discontinuous brightness enhancements of 252P/LINEAR. Before the first enhancement, the NIR polarization degrees of the comet were far lower than those of ordinary comets at a given phase angle. Soon after the activation, however, they increased by ~13% at most, showing unusual blue polarimetric color over the J and H bands (−2.55% μm−1 on average) and bluing of the dust color in both J−H and H−KS. Throughout the event, the polarization vector was marginally aligned perpendicular to the scattering plane (i.e., θr = 4.6°–10.9°). The subsequent postperihelion reactivation of the comet lasted for approximately 1.5 months, with a factor of ~30 times pre-activation dust mass-loss rates in the RC band. Conclusions. The marked increase in the polarization degree with blue NIR polarimetric color is reminiscent of the behavior of a fragmenting comet D/1999 S4 (LINEAR). The most plausible scenario for the observed polarimetric properties of 252P/LINEAR is an ejection of predominantly large (well within the geometrical optics regime) and compact dust particles from the desiccated surface layer. We conjecture that the more intense solar heating that the comet has received in the near-Earth orbit would cause the paucity of small fluffy dust particles around the nucleus of the comet.

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.

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