An official website of the United States government
Here, we demonstrate that polarization properties show a wide diversity depending on viewing angles. To simulate images of a supermassive black hole and surrounding plasma, we performed a full-polarimetric general relativistic radiative transfer based on three-dimensional general relativistic magnetohydrodynamics models with moderate magnetic strengths. Under an assumption of a hot-jet and cold-disk in the electron temperature prescription, we confirmed a typical scenario where polarized synchrotron emissions from the funnel jet experience Faraday rotation and conversion in the equatorial disk. Further, we found that linear polarization vectors are inevitably depolarized for edge-on-like observers, whereas a portion of vectors survive and reach the observers in face-on-like cases. We also found that circular polarization components have persistent signs in the face-on cases, and changing signs in the edge-on cases. It is confirmed that these features are smoothly connected via intermediate viewing-angle cases. These results are due to Faraday rotation/conversion for different viewing angles, and suggest that a combination of linear and circular polarimetry can give a constraint on the inclination between the observer and black hole’s (and/or disk’s) rotating-axis and plasma properties in the jet–disk structure. These can also lead to a more statistical and unified interpretation for a diversity of emissions from active galactic nuclei.
more »
« less
This content will become publicly available on February 13, 2026
Polarization enhancement of contrast through a water surface
When imaging underwater scenes from above the water surface, the reflection from the air–water interface creates an obscuring background that varies with illumination and viewing angles. It is well known that the reflected light is horizontally polarized, and using a vertically transmitting polarizing filter is a common technique to improve the contrast of underwater scenes. However, to our knowledge, no quantitative measurements of polarization-enabled contrast enhancement have been reported in the literature. In this work, panchromatic and RGB division-of-focal-plane polarization cameras were used to record images of black and white tiles submerged in water for determining contrast as a function of viewing angle, both without a polarizer and with a vertical polarizer. Experiments were conducted in two outdoor locations and in a black tub indoors with controlled color and brightness of the reflected background. The maximum contrast through a vertical polarizer occurred near the Brewster angle, but the amount of contrast enhancement (the ratio of contrast through a polarizer to contrast without a polarizer) was found to increase until much larger angles. Also, the observed changes in contrast resulting from changing properties of the reflected background were consistent with the Fresnel reflection coefficients.
more »
« less
- PAR ID:
- 10571825
- Publisher / Repository:
- Optical Society of America
- Date Published:
- Journal Name:
- Applied Optics
- Volume:
- 64
- Issue:
- 6
- ISSN:
- 1559-128X; APOPAI
- Format(s):
- Medium: X Size: Article No. 1443
- Size(s):
- Article No. 1443
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Light’sinteraction with objectsurfacesthrough anisotropic reflection– where reflected light varies with viewing angles–offers significant potential for enhancing visual capabilities and assisting informed decision-making. Such ubiquitous light transfer phenomenon supports directional information encoding in sensing and dynamic display applications. We present LumosX, a set of techniques for encoding and decoding information through light intensity changes using 3D-printed optical anisotropic properties. By optimizing directional reflection and brightness contrasts through off-the-shelf materials and precise control over processing parameters (e.g., extrusion volume, raster angles, layer height, nozzle positioning), we enable cost-effective fabrication of visually enhanced objects. Our method supports modular assembly for highly curved regular surfaces and direct printing on top of relatively flat curved surfaces, enabling flexible information encoding for diverse applications. We showcase LumosX’s effectiveness through various indoor and smart urban sensing scenarios, demonstrating significant improvements in both human interaction and autonomous machine perception.more » « less
-
Polarization aberrations are found in most optical components due to a materials differing response to s- and p-polarizations. This differing response can manifest either as diattenuation, retardance, or both. Correction of polarization aberrations, such as these, are critical in many applications such as interferometry, polarimetry, display, and high contrast imaging, including astronomy. In this work, compensators based on liquid crystal polymer and anti-reflection thin-films are presented to correct polarization aberrations in both transmission and reflection configurations. Our method is versatile, allowing for good correction in transmission and reflection due to optical components possessing differing diattenuation and retardance dispersions. Through simulation and experimental validation we show two designs, one correcting the polarization aberrations of a dichroic spectral filter over a 170nm wavelength band, and the other correcting the polarization aberration of an aluminum-coated mirror over a 400nm wavelength band and a 55-degree cone of angles. The measured performance of the polarization aberration compensators shows good agreement with theory.more » « less
-
Polarization aberrations are found in most optical components due to a materials-differing response tos- andp-polarizations. This differing response can manifest either as diattenuation, retardance, or both. Correction of polarization aberrations, such as these, are critical in many applications such as interferometry, polarimetry, display, and high contrast imaging, including astronomy. In this work, compensators based on liquid crystal polymer and anti-reflection thin-films are presented to correct polarization aberrations in both transmission and reflection configurations. Our method is versatile, allowing for good correction in transmission and reflection due to optical components possessing differing diattenuation and retardance dispersions. Through simulation and experimental validation we show two designs, one correcting the polarization aberrations of a dichroic spectral filter over a 170nm wavelength band, and the other correcting the polarization aberration of an aluminum-coated mirror over a 400nm wavelength band and a 55-degree cone of angles. The measured performance of the polarization aberration compensators shows good agreement with theory.more » « less
-
We demonstrate calibration and operation of a single wavelength (660 nm) Mueller matrix ellipsometer in normal transmission configuration using dual continuously rotating anisotropic mirrors. The mirrors contain highly spatially coherent nanostructure slanted columnar titanium thin films deposited onto optically thick gold layers on glass substrates. Upon rotation around the mirror normal axis, sufficient modulation of the Stokes parameters of light reflected at oblique angle of incidence is achieved. Thereby, the mirrors can be used as a polarization state generator and polarization state analyzer in a generalized ellipsometry instrument. A Fourier expansion approach is found sufficient to render and calibrate the effects of the mirror rotations onto the polarized light train within the ellipsometer. The Mueller matrix elements of a set of anisotropic samples consisting of a linear polarizer and a linear retarder are measured and compared with model data, and very good agreement is observed.more » « less
