In Memoriam:  Alfred Josef Thelen, 1929-2010

Alfred ThelenAlfred Josef Thelen, an OSA Fellow Emeritus known for his contributions to the field of optical thin films, died on April 19, 2010, in Frankfurt, Germany.  He was 81.

Thelen’s accomplishments included work in such areas as antireflection coatings, reflection and minus filters, edge filters, beam splitters, broad- and narrow-bandpass filters and polarizers. 

Thelen received his early education in his home town of Frankfurt, Germany.  He studied physics at the Technical School for Higher Education in Darmstadt, one of the great German universities, where he was a teaching assistant in experimental and theoretical physics and in applied mathematics (1949-1955). His dissertation was on the subject of conducting antireflection coatings on glass.

In 1955, Thelen went to Santa Rosa, California, to work for the Optical Coating Laboratories Incorporated (OCLI).  He returned to Germany in 1956 just long enough to obtain a Ph.D. from the University of Karlsruhe (1959).  His thesis was on the lubrication of cylindrical bearings with oil– antifreeze mixtures.  He then returned to the OCLI in Santa Rosa, becoming vice president for Research and Development in 1961. Then, in 1969 Alfred Thelen joined Balzers AG in the Principality of Liechtenstein, where, in 1976, he was named director and chief of the Thin Films Group, and where he remained for eight years before returning to the Optical Coating Laboratories in Santa Rosa as senior vice president and director of technology.

Eventually Thelen started to miss his European heritage.  He returned to Germany in 1985 to work as research director at Leybold–Heräus.  In 1990, he became a professor at the University of Kaiserslautern.  In the same year he started an optical thin-film interference-coating consulting business in Frankfurt, Germany.  In the mid-1990s, Thelen became the European representative for the OptiLayer thin film design software.

Thelen was the author of Design of Optical Interference Coatings (McGraw-Hill, 1988) and numerous other publications, including book chapters, papers in refereed journals and conference proceedings.  He also held at least 19 US patents. 

An OSA member for 48 years, Thelen served on the Optical Interface Coatings (OIC) advisory committee.  He was elected as a Fellow in 1962.

Thelen died on the first anniversary of his wife’s death, a day that also coincided with her birthday.  He is survived by two children and five grandchildren.