Related Experiment Video
Updated: Jun 11, 2026

07:03
Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals
Published on: August 15, 2018
Summary
This study details methods for measuring retardation and optical axis alignment in birefringent crystals. These procedures ensure crystal quality and performance for optical applications.
Area of Science:
- Optics and Photonics
- Materials Science
Background:
- Birefringent crystals are crucial optical components.
- Precise characterization of their optical properties is essential for device performance.
Purpose of the Study:
- To present standardized procedures for evaluating key optical properties of birefringent crystals.
- To enable accurate measurement of retardation, its uniformity, and optical axis alignment.
Main Methods:
- Describes experimental setups and protocols for retardation measurement.
- Details techniques for assessing the uniformity of retardation across crystal surfaces.
- Outlines methods for precise optical axis alignment determination.
Main Results:
- Established reliable procedures for quantifying retardation values.
- Demonstrated methods to assess and ensure retardation uniformity.
- Provided techniques for accurate optical axis alignment.
Conclusions:
- The described procedures facilitate the accurate characterization of birefringent crystals.
- These methods are vital for quality control and optimizing performance in optical systems.
- Standardized measurement protocols enhance reproducibility and reliability in optical device fabrication.
Related Concept Videos
Retarders
Retarders are chemical admixtures designed to extend the setting time, which is especially useful when there is a delay in sequential concrete pours to prevent cold joints and to achieve a cohesive structure. Retarders, when used in appropriate amounts, can also enhance the architectural appearance of exposed aggregate finishes.
The function of retarders is to delay the setting of concrete, and this effect can be measured using a penetration test. The retardation process involves adding...
The function of retarders is to delay the setting of concrete, and this effect can be measured using a penetration test. The retardation process involves adding...
Determination of Crystal Structures
In the late 1800s, the revelation that light extended beyond visible wavelengths led to the discovery of X-rays by Wilhelm Roentgen. Recognized as high-energy electromagnetic radiation with short wavelengths, X-rays prompted exploration into their interaction with crystals. Max von Laue proposed in 1912 that the periodic arrangement of atoms, ions, or molecules in crystals would cause them to diffract X-rays, a hypothesis confirmed through experiments with copper sulfate and zinc sulfide...
Imperfections in Crystal Structure: Stoichiometric Point Defects
Schottky defects arise when some lattice points in a crystal, such as those in NaCl, remain unoccupied, creating lattice vacancies without disturbing the overall electrical neutrality of the crystal. This defect is common in ionic crystals where the positive and negative ions are similar in size, as seen in sodium chloride and cesium chloride. The presence of Schottky defects enables the crystal to conduct electricity to a small extent through an ionic mechanism. Electric fields cause nearby...
Crystal Density
The crystal lattice structure of a material allows us to determine how many molecules exist in its unit cell. With this information, alongside the unit-cell parameters - three distance parameters (a, b, c) and three angular parameters (α, β, γ).Density (ρ) = (Z × M) / (a × b × c × NA)where:Z is the number of formula units per unit cellM is the molar mass of the substancea, b, and c are the edge lengths of the unit cellNA is Avogadro’s numberFor a simple cubic lattice, atoms are located only at...
Silica Gel Column Chromatography: Overview
Silica gel column chromatography is a technique for separating compounds using a column packed with silica gel as the stationary phase. This method relies on differences in the polarity of compounds. Based on their polarities, compounds move between the stationary phase (silica gel) and the mobile phase (the solvent), forming discrete bands in the column.
Polar components tend to bind strongly to the silica gel, causing them to move slowly through the column. In contrast, nonpolar compounds...
Polar components tend to bind strongly to the silica gel, causing them to move slowly through the column. In contrast, nonpolar compounds...
Measuring Reaction Rates
Polarimetry finds application in chemical kinetics to measure the concentration and reaction kinetics of optically active substances during a chemical reaction. Optically active substances have the capability of rotating the plane of polarization of linearly polarized light passing through them—a feature called optical rotation. Optical activity is attributed to the molecular structure of substances. Normal monochromatic light is unpolarized and possesses oscillations of the electrical field in...

