Related Experiment Video
Updated: Jul 7, 2026
05:54
Polarization-Sensitive Two-Photon Microscopy for a Label-Free Amyloid Structural Characterization
Published on: September 8, 2023
Polarization Structures in Parhelic Circles and in 120 degrees Parhelia.
Applied Optics
|February 13, 2008
Summary
Halos like parhelic circles and 120-degree parhelia shift position when viewed through a rotating polarizer. This phenomenon is caused by polarization-sensitive internal reflection within ice crystals.
Area of Science:
- Atmospheric optics
- Crystallography
Background:
- Halos are optical phenomena caused by light interacting with ice crystals in the atmosphere.
- Plate-oriented crystals with vertical main axes are known to produce specific halo patterns.
Purpose of the Study:
- To investigate the positional changes of parhelic circles and 120-degree parhelia when observed through a rotating polarizer.
- To elucidate the mechanism behind these observed halo displacements.
Main Methods:
- Theoretical analysis of light interaction with oriented ice crystals.
- Polarization-sensitive observations using a rotating polarizer.
- Visual and instrumental recording of halo displacements.
Main Results:
- Parhelic circles exhibit vertical movement, with maximum shifts at 90-120 degrees azimuthal distance from the Sun.
- 120-degree parhelia display both vertical and horizontal displacements.
- Observed shifts range from 0.1 to 0.3 degrees, varying with solar elevation.
Conclusions:
- The observed halo displacements are attributed to polarization-sensitive internal reflection within prism faces of ice crystals.
- This study provides observational evidence and theoretical support for the polarization-dependent nature of certain halo phenomena.
Related Concept Videos
01:17Graphs of Polar Equations
The polar coordinate system represents points using a distance from a central point (the pole) and an angle from a reference direction (the polar axis). Unlike rectangular coordinates, polar coordinates are ideal for graphing curves with radial symmetry or periodic behavior.Some general forms of graphs in polar coordinates include the following:Equation of a Circle (Centered at the Pole):A graph where the radius remains constant for all angles traces a circle centered at the pole:Equation of a...
01:19Polar Curves
The spirograph is a versatile tool for visualizing the relationship between geometry and mathematical representation. In particular, it demonstrates how polar coordinates offer an alternative framework for describing curves in comparison to Cartesian coordinates. Instead of specifying a point by its horizontal and vertical displacements (x, y), polar coordinates use a radius r, the distance from the origin, and an angle θ, measured counterclockwise from the polar axis. This system is...
01:27Polar Coordinates: Problem Solving
Directional radiation patterns are central to antenna analysis, as they illustrate how signal strength varies with direction. These patterns are often modeled using polar plots, where the radial distance from the origin represents signal intensity at a given angle. A commonly used idealized form is the four-lobed rose curve, which captures the concept of directional beams in a simplified mathematical form.The four-lobed rose curve, described by r = cos(2θ), features four symmetric lobes, each...
01:29Polar Equations of Conics
A conic section can be defined in polar coordinates as the set of all points whose distance from a fixed point, known as the focus, bears a constant ratio to their distance from a fixed line, known as the directrix. This constant ratio is called the eccentricity. This definition unifies all types of conic sections—ellipses, parabolas, and hyperbolas—under a single framework. When the focus is positioned at the origin of the polar coordinate system, a single polar equation can describe any conic...
01:18Frost Circles for Different Conjugated Systems
The inscribed polygon method is consistent with Hückel’s 4n + 2 rule and helps to learn whether the given cyclic compound is aromatic or not. The compound is stable and aromatic if every bonding molecular orbital (MO) is completely filled with a pair of electrons. However, if the non-bonding or antibonding orbitals are filled with electrons, the compound is unstable and not aromatic. Consider the Frost circle diagrams for cycloalkenes containing 4 to 8 carbons.
01:30Polar Coordinate System
The polar coordinate system provides a natural way to describe points in the plane when distances and directions are more meaningful than horizontal and vertical displacements. It is especially useful for modeling non-rectangular regions such as circles and spirals, where symmetry about a center point is easier to express than it is in a rectangular grid. A familiar example is a ship’s plan position indicator, which marks detected targets as dots positioned relative to the ship at the display’s...