WASHINGTON, July 22, 2022 – The polarization of light underpins a variety of recent technological innovations, including 3D cinema and LCDs. In LCDs, tiny electronically controllable liquid crystal elements are embedded between polarizers. If instead other transparent polarization-changing films – such as cellophane wrapping paper and packaging tape – are placed between a set of polarizers, a range of polarization-filtered colors can be observed.
In which American Journal of Physicsof AIP Publishing, Aaron Slepkov of Trent University in Canada examines the physics of how such colors arise, how they can be controlled, and why subtle changes in viewing angle, sample orientation, and the order of film layers between polarizers can have dramatic effects on the observed colors to have.
The research emphasizes visual examples of concepts related to birefringence, such as addition, subtraction, and order of operations. For example, the non-commutative nature of birefringent addition is typically illustrated using formal matrix mathematics. In this case, however, the researchers use color visualization.
“I use a visual color language to illustrate subtle physics that are often only demonstrated mathematically,” Slepkov said.
He was inspired in part by the work of artist Austine Wood Comarow, who made a career of applying polarized filtered color techniques to fine art. Austine coined the term “polage” or polarization of collage to refer to her art.
Austine created a wide range of work using intricate layers of cut cellophane and other birefringent polymer films interspersed with layers of film polarizers. Her pieces range from small, one-off pieces that fit on a shelf to massive, career-spanning installations at institutions such as Disney Epcot Center in 1981 and Gyeongsangnam-do Institute of Science Education in Jinju, South Korea in 2017.
“In this work I clarify the connection between polarization filtering and the observed colors. I show how different aspects of birefringence in ordinary household films present opportunities and challenges for their use in art,” Slepkov said.
To produce polarization-filtered color, all that is needed is a birefringent sample placed between polarizers that form a polarization gate. Many household items can offer a kaleidoscopic range of colors and patterns.
For example, transparent plastic cutlery provides a classic demonstration where localized stress in the polymer structure results in differential birefringence, observable through a polarization gate. Likewise, somewhat haphazardly folded kitchen wrap, gift basket wrap, and layered tape can create intricate images reminiscent of stained glass windows.
“Manipulating birefringent film to create color images is fun and intellectually stimulating. Much of the nuanced physics of polarization, birefringence, retardation, and color theory can be observed in this accessible but far-reaching endeavor,” Slepkov said.
The article “Painting in Polarization” was written by Aaron Slepkov. The article will appear in the American Journal of Physics on July 22, 2022 (DOI: 10.1119/5.0087800). It is then available at https://aip.scitation.org/doi/full/10.1119/5.0087800.
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American Journal of Physics
Painting in polarization
Article publication date
July 22, 2022
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