Polarized light is critical for a wide variety of optical applications. While optical equipment is often designed to modify light intensity and wavelengths, polarization offers its own set of unique benefits and properties. It helps to filter light to specific wavelengths, enhance laser beams, and reduce the effects of reflection and refraction of light waves.
Polarization is used to perform material stress testing and conduct scatter analysis of biological, chemical, and pharmaceutical samples. The polarization of light is also responsible for the effects of 3D glasses and glare-reducing eyewear and can be used to provide clarity in photography, microscopy, and telescopy.
Light consists of both electrical and magnetic energy, and is therefore an electromagnetic wave. It is also a transverse wave, which means that the light’s electric field oscillates at a right angle to the axis along which the light travels. If the oscillation is random, the light is scattered in many directions. This is the primary difference between polarized vs unpolarized light. Unpolarized light can be seen coming from common light sources, such as light bulbs and the sun. Polarization narrows the field of light by limiting the angles at which the light reaches the viewer or sensor, reducing scatter and reflection. This process is most evident in lasers, which consist of one directed beam of light energy.
Polarization control refers to the methods used to ensure optimal polarization in optical operations. Manufacturers and operators of optical equipment modify the reflectivity, beamsplitter ratios, and insertion loss based on the desired polarization. Using a variety of methods, users modify the direction and flow of light waves to reduce glare and eliminate energy outside the desired range. The result is targeted light that produces superior imaging, color, and contrast without interference.
Not only does polarization block unwanted energy for visual applications like cameras and microscopes, but it can also be used to detect material properties by measuring the changes in light waves when they interact with a sample. By evaluating the fine changes in light polarization from reflected and transmitted light, users can determine the chemical, magnetic, mechanical, and other properties of the material.
Each of these operations requires extreme precision to ensure optimal performance and reliable results. To meet specific needs for polarization in a variety of applications, many polarizing methods have been developed. Each method uses particular materials that control the flow and direction of light beams through the use of absorption, transmission, or reflection.
Unpolarized light consists of waves of light that oscillate at random, transmitting light along multiple axes. Polarizers and waveplates filter, redirect, or otherwise modify the light waves to eliminate light that is not moving along the desired axis. Polarization typically isolates waves that either run parallel or perpendicular to the axis of the light’s linear motion.
Polarizers are optical components that only transmit light waves along an axis relative to the light’s incident polarization. In essence, they allow the flow of light to move through the polarizer along the desired axis while rejecting the light moving along other axes. Polarizers can be divided into three categories based on the way they filter light:
Unlike polarizers, which simply filter out undesired polarizations, waveplates modify the flow of light without reducing, displacing, or deviating the beam. Instead, they convert the flow of polarization into a new state by modifying the speed of certain polarizations. To modify the light at different polarizations, waveplates are composed of materials with a structured crystal lattice, such as quartz or calcite. The plate is cut at an angle in relation to the crystalline structure that allows users to modify the velocity and refraction of certain polarizations. This converts the orientation of the polarized light from linear to circular or vice versa.
Polarized light is divided into three different polarization classes, based on the orientation of the electric field:
Polarization is used to facilitate a wide range of optical applications to reduce glare and reflections, eliminate interference from scattered light, and enhance color and light contrasts. It is also critical for optics in analytical applications such as stress detection, chemical and molecular analysis, and microscopic specimen identification and photography.
Whether you are using polarized optics to enhance your nature photography or to complete detailed imaging of microscopic organisms, Evaporated Coatings, Inc. has the perfect optical coating for your needs. With more than 60 years of experience in the optical coating industry, we understand the need for the utmost precision and clarity in optics applications. We are committed to providing our customers with outstanding optical component coatings for even the most complex systems. Each of our optical coatings is skillfully applied to facilitate and enhance the optical properties of components to ensure optimal light transmission, reflection, and polarization. Our coatings can be added to a variety of substrates, from glass and polymer to semiconductors and fiber optics.
Evaporated Coatings Inc. is an industry leader in the development of optical coatings for a wide range of applications. Our comprehensive selection of optical coatings include: