In early January the optical community lost one of the most well-known and respected optical designers, Arthur Cox. He was actively designing lenses until a few days before his death at 92, in Newport Beach, California.
Cox graduated with honors from the University of Durham in England, earned a master’s degree in mathematics at Cambridge University (Christ College), and was awarded a doctorate from the University of Newcastle Upon Tyne.
He began his career at Aldis Brothers in Birmingham, England, as an optical designer and soon became known for his skill. After three years, he was offered a job at Taylor, Taylor and Hobson in Leicester, England, where he worked for one of the most respected optical designers of that period, Arthur Warmisham.
During World War II, Cox worked on a wide range of optical lenses and systems, mainly for military applications, for which he was awarded a substantial number of patents. Cox, initially used log tables and a circular slide rule to perform computations. He once told me that the weather was so cold in the winter that he wore gloves with the fingers removed to facilitate using the circular slide rule. In those days he was very industrious, not only designing lenses but also manufacturing them. He had a lifelong interest in the use of aspheric surfaces.
He also became a prolific writer. His first book, Photographic Optics, published in 1943, is in its 14th edition and has been published in several languages.
In 1947, Arthur moved his family to the United States when he joined Farrand Optical Company in New York. There he worked on a number of optical systems, mainly for use in military instruments. At that time he completed his second book, Engineering Optics, which he had started with Ken Habell when they both worked at TT & H.
In 1951, Cox was appointed chief optical designer at the Bell & Howell Company in Chicago. It was there that Cox did his most productive work and was responsible for developing and training a team of optical designers. At Bell and Howell he was responsible for creating a wealth of products, including the efficient manufacture of zoom lenses. He was also responsible for developing methods for manufacturing aspheric surfaces.
During his time at Bell & Howell, the company developed the optical system for the Surveyor Spacecraft that landed on the moon. In addition Arthur continued his writing, authoring A System of Optical Design, a 600-page book published in 1964, which is considered the “bible” of optical design. It is safe to say that it was read by every practicing optical designer. In the book, Cox not only derived all of the mathematics required in ray tracing but included an impressive collection of patents.
He retired from Bell & Howell in 1967 as vice president of optics, but he did not retire from optics. During the next five years he completely rewrote Photographic Optics and consulted for a number of companies throughout the world. In early 1972, he returned to Bell & Howell as president of the Optics Division. He remained there for five years before finally retiring-but not for long. He was soon back designing optical systems, particularly zoom lenses. He also continued to present papers at SPIE meetings, the last one in April 2005, when he was 90 years old.
Cox was a Fellow of the Institute of Optics of London, a Fellow of the Optical Society of America, and a Fellow of the International Society of Photo Optical Engineers. He held more than 50 patents.
Arthur was preceded in death by his wife of over 50 years, Vida, to whom he dedicated all of his books, and a son, Michael. He is survived by one son, Kenneth and his wife Katy of Houston, TX, and two daughters, Judith Maxwell and her husband Jay of Newport Beach, CA., and Peggy Krubinski. He had 11 grandchildren.
We have lost a giant in the optical industry. He was one of a kind and I, for one, will miss him.
Fred Abbott
D.Sc., C.Phys,
F.Inst P., F.O.A., F.SPIE
Westlake Village, CA 91361
[email protected]
Laser fusion energy holds promise for the energy crisis
As a long-time reader of Laser Focus World, I would like to especially congratulate you on the September issue about the energy crisis and what photonics and lasers can do (“Photonics and the energy crisis,” September 2006, p. 69; www.laserfocusworld.com/articles/272166). You may have ignored laser-driven fusion energy because there seemed to be not much new. Please note that a contribution to the topic I submitted with George Miley appeared in your magazine 20 years ago, causing some attention (H. Hora and G.H. Miley, “New avenues to success in laser fusion,” Laser Focus 20(2) 59 [1984]). You may be interested to know that the petawatt-picosecond laser pulses have now led to a unique alternative to mainstream research, possibly leading to a method of very-low-cost fusion-energy production. The research was published in December 2006 at the Australian Physics Congress in Brisbane and in the Journal de Physique IV 133 “Plasma blocks from nonlinear force generated skin layer acceleration for ignition of a fusion flame in nearly uncompressed solid DT.”
Heinrich Hora,
Emeritus Professor
University of New South Wales
Sydney 2052, Australia
[email protected]
Earlier research demonstrated CRDS with LEDs
We read with interest your news report on the use of light-emitting diodes (LED) to perform cavity-ringdown spectroscopy (“LED approach may yield inexpensive field systems,” January, p. 41; www.laserfousworld.com/articles/282660) We believe that your readers would like to know that we first reported the use of an LED as part of a cavity-enhanced optical-absorption measurement more than two years ago. Using a weak blue LED, we were able to detect nitrogen dioxide (NO2), a criteria air pollutant, with a detection limit of approximately three parts per billion with 10 seconds integration.1 In this device, we chose to measure the phase shift, instead of the completely equivalent “ringdown time,” so as to minimize cost and maximize sensitivity.
With improvements in optical coupling, use of a brighter LED, and implementation of very-low-noise heterodyne detection techniques, we have been able to dispense with the use of a photomultiplier tube and photon-counting techniques altogether. The current version of the monitor has a detection limit of about 20 parts per trillion which is equivalent to an extinction coefficient of 0.02 mm-1.2 The monitor has also proven to exhibit great stability, showing baseline drift of less than 0.2 ppb NO2 in 24 hours. Furthermore, the monitor has been designed to be cost-competitive with current technology capable of measuring ambient concentrations of NO2 and is constructed within a standard 19 in. rack-mounted instrumentation box. We are also currently developing a version of the instrument for the measurement of particulate and aerosol concentrations.
Andrew Freedman
Paul L. Kebabian
Center for Sensor Systems and Technology
Aerodyne Research
Billerica, MA
[email protected]
REFERENCES
1. P.L. Kebabian, S.C. Herndon, A. Freedman, “Detection of nitrogen dioxide by cavity attenuated phase shift spectroscopy,” Anal. Chem. 77, 724 (2005).
2. P.L. Kebabian, E.C. Wood, S.C. Herndon, and A. Freedman, “A practical alternative to chemiluminescence-based detection of nitrogen dioxide: cavity attenuated phase shift spectroscopy,” Anal. Chem., submitted for publication.