ISO 9001 - AS 9100 - ITAR Toll Free (US): +1 (888) 893-9992 International: +01 (603) 893-6888

Control the light, see your world

Standard & Custom Optical Filters and Coatings

Women in Optics – Dr. Mary Banning Friedlander

If you were to look at the number of females that are currently working in the Science, Technology, Engineering and Mathematics fields (STEM), you would probably be a bit disheartened. Women remain underrepresented in these fields even though there has been a strong push to get more of us into STEM careers, including my field of optics & photonics. Women make up almost half of the American workforce but only 27% of that is of STEM employment. This caused me to wonder if there had ever been any particularly outstanding women in the optics field that have somehow been forgotten. To my delight, I discovered some information about a fascinating woman, who was a true trail blazer and role model for women in the optics industry today.

 Her name was Dr. Mary Banning Friedlander, and she was an innovative, hands-on optical physicist in the 1940’s who made a genuine and long-lasting mark on our industry. During her short, but wildly successful career in the 1940s and 50s, she made major contributions to the American war effort and advanced the level of optics technology. Her development of multi-layer, low reflecting coatings formed the basis of much of what Andover Corporation manufactures today.

 Ms. Banning obtained her Bachelor of Arts degree in Physics at Vassar College and acquired her PhD in Physics from Johns-Hopkins University in 1941. Her post-doctoral fellowship took place at the University of Rochester’s Institute of Optics in New York- the birthplace of optics. This was a huge accomplishment at the time, as these opportunities were usually reserved for males. In the 1940’s, only 3.8 percent of women in the United States completed four years or more of higher education and many colleges refused to accept any women at all.

 At the start of her fellowship, she focused her efforts on wartime research to assist the United States government during World War II. The Institute of Optics was one of the nation’s key centers of scientific research at that time. Banning established the Thin Films Laboratory, which she equipped with some of the first vacuum coating chambers. World War II was the first conflict where victory was highly dependent on which side had the best technology, and both sides struggled to achieve dominance. Optical inventions, like Metascopes, the first infrared viewers, were developed by the Institute of Optics. Providing Allied troops with the ability to “see” at night to target enemy soldiers and vehicles was especially critical to the success of airborne operations in Europe.

 Among many optical innovations, Banning and her colleagues developed multi-layer low-reflecting coatings that were used in target acquisition, range finding and sighting for military equipment. She also aided in the development and deployment of “corner cube reflectors”, which provide extremely accurate range measurements between two separated units, especially useful in clandestine aircraft landings. Military optical applications often require high performance coatings that can withstand large environmental shifts, exposure to contaminants and many other rigors common to the battlefield. Mary Banning had both the intellect and fortitude to produce these high-quality coatings that helped sustain America’s international defense.

The Institute of Optics Director, Dr. Brian O’Brien Jr., describes projects led by Mary Banning in further detail, “I did work for Dr. Mary Banning, as did several other undergraduates… we did a lot of coating work during the war. This included multi-layer low-reflecting coatings, nickel neutral density filters, partial reflecting coatings, etc.” These same coatings are regularly manufactured today at Andover Corporation.

 Dr. Brian O’ Brien Jr. went on to say, “I remember one job we did producing 50% coatings on 45/90 prisms for our entire fleet of submarine periscope cameras. These were not done by vacuum evaporation but by heat decomposition of titanium tetrachloride into titanium dioxide coating on glass. In 1947 Mary Banning wrote a classic paper explaining how to deposit multi-layer filters and how to control their thickness. She also described the 1943 development of the polarizing beam splitter in this paper as well.” After the war, Mary’s technical expertise was well known and she was asked to address a senior group of officers and politicians on “Atomic Energy and Air Power” on Air Force Day in 1946.

 In September of 1947, Mary married Gardner Louis Friedlander and the couple had two children, one of whom died prematurely. In the years following, Dr. Friedlander taught at Milwaukee Downer College and the University of Wisconsin until her retirement in 1975.  Mary passed away from emphysema complications in 2001 at the age of 85, and her husband Gardner died just two years later in a tragic skiing accident.

 Mary Banning’s optical innovations are still widely used today. She stands out as a woman of courage and ambition who pursued her dreams and achieved great success despite the obstacles she faced. She refused to let discrimination stand in her way, and in the end was recognized as a pioneer in optics and a role model for women who wish to pursue careers in the optics & photonics industry.



Burton, K. (2020, July 31). The Scientific and Technological Advances of World War II: The National WWII Museum: New Orleans. The National WWII Museum | New Orleans.

Daly, K. (2016, December 15). Women in Optics: Invention of multi-layer low reflecting coatings. Lumetrics.

Published by Erin Duffin, & 11, J. (2021, June 11). Americans with a college degree 1940-2018, by gender. Statista.

Refermat, S. (n.d.). Optical Thin Films at The Institute of Optics: A Brief History.


UniversityofRochester. (2016, December 7). Developing the Optics that Helped Win World War II. YouTube.





Back to Blog

Related Articles

Thomas Grubb: Ireland's Pioneer of Telescope Design

This St. Patrick's Day, we explore the life and contributions of Ireland's own Thomas Grubb, a...

Cost Effective Optical Fabrication

When purchasing an optical filter, most customers are primarily focused on the optical...

The Power of Flexibility

Flexibility is a powerful attribute for companies and personal well-being alike. In a manufacturing...