Memorial Tributes: Volume 27
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  • ANTHONY E. SIEGMAN (1931-2011)
    ANTHONY E. SIEGMAN

     

    SUBMITTED BY
    THE NAE HOME SECRETARY

    ANTHONY EDWARD SIEGMAN, known for his contributions to laser resonators and optical beam propagation, for his co-authorship of the first paper that theoretically predicted what would later be called parametric fluorescence, and for primary contributions to laser mode locking, died on October 7, 2011, at age 79. He was an educator of the first order, especially well known for his widely used textbook, Lasers (University Science Books, 1986), for his many productive and talented students, and for his overall impact on optical science and engineering.

    The oldest of three boys, Tony was born on November 12, 1931, in Detroit. He grew up in rural Michigan, northwest of Detroit, where his mother was an elementary school teacher, and his father was the controller for an ice and fuel company. He attended local schools in his early years, but in high school he switched to the all-boys Catholic Central High School, which gave him an opportunity to share a daily commute with his father. Outside of school, Tony repaired an aged outboard motor for boating on the nearby lake, reflecting an early interest in practical matters and making things work. In the late 1940s, Harvard University instituted a national scholar program in an effort to increase the geographic and economic diversity of its students. Two students from each state received substantial scholarships. Siegman was one of the scholarship winners from Michigan in 1949. Since Harvard had no engineering school, Siegman followed the engineering science and applied physics track within the physics department. He took five courses per semester instead of the usual four, which, with the addition of a few extra summer classes, enabled him to receive his bachelor’s degree summa cum laude in 1952 after only three years.

    After graduation, he joined the Hughes Research Laboratory cooperative program in the summer of 1952. The program required entry-level engineers to split their work weeks between their jobs and graduate studies so that, after two years, they would earn a master’s degree in applied physics. Tony did research on traveling wave tubes while working toward an MS degree in applied physics at the University of California–Los Angeles, which he earned in 1954. Continuing the brisk pace he set at Harvard, Siegman finished his academic work in a year and a half. Tony’s first publication, in 1953, was “Helix Impedance Measurements Using an Electron Beam.”

    Siegman’s first boss at Hughes was Dean A. Watkins, who left after a year for a faculty position at Stanford University. Shortly thereafter, Watkins invited Siegman and another Hughes fellow to come to Stanford to study for a doctorate in electrical engineering. Tony received his PhD in electrical engineering in 1957, with a dissertation on microwave noise in electron beams and traveling-wave tubes. That same year, he and Watkins (NAE 1968) published two papers that developed a new technique for the analysis of traveling wave tubes, providing excellent examples of Tony’s ability to blend sophisticated mathematics with strong physical insight, a characteristic that permeated his entire body of work. Even before he finished his doctorate, Stanford hired him as an acting assistant professor in 1956 so that he could teach an electrical engineering class. He continued as a faculty member at Stanford for over 40 years, becoming a full professor in 1964 and retiring from his Stanford position as the Burton J. and Ann M. McMurtry Professor of Engineering in 1998. During his Stanford career, Siegman supervised some 40 PhD dissertations.

    While his thesis work led to Siegman’s appointment as assistant professor in electrical engineering, he soon changed fields and hired three students to work on masers, which had recently been predicted and were the subject of significant investigation. The nonlinear-optics research on Stanford’s campus grew out of the microwave group at the Ginzton Laboratory, which was then housed in its original building.

    A few years later, with three maser-oriented dissertations in progress and his first textbook, Microwave Solid-State Masers (McGraw-Hill, 1964), not quite finished, Tony made a second major change in research direction and began work on lasers, fast on the heels of the May 1960 announcement of Theodore Maiman’s demonstration of the ruby laser. Siegman and other young faculty members and students focused their efforts on improving the laser. Tony and his first graduate student in lasers, Burton J. McMurtry, published “Photomixing Experiments with a Ruby Optical Maser and a Traveling-Wave Microwave Phototube” in the inaugural issue of Applied Optics in 1962. Using an early laser following a design from Raytheon and a TWT with a thermionic cathode, he observed the beats between the third and seventh nearest neighboring modes, the first observation of simultaneous oscillation of different axial modes. In the conclusion of their paper the authors note that their TWT could be viewed as a super-heterodyne receiver with the cathode acting as the mixer and the helix as an amplifier.

    Siegman was one of the first to blaze a path into quantum electronics. “At that time, microwave electronics was one of Stanford's particular strengths and an intellectually exciting field,” Siegman once explained. “For me, it soon led to a natural evolution into the emerging areas of lasers and optical electronics.” In a classic 1961 paper, Tony, along with Bill Louisell and Amnon Yariv (NAE 1976), gave the first description of the noise associated with parametric amplification. This led to the discovery in 1968 of what was then termed parametric fluorescence at optical frequencies. Within 10 years, this type of light source became the standard for experiments with entangled photons, Bell inequalities, and quantum information. Many years later, the “noise” described in the paper was harnessed as a squeezed vacuum state that led to vastly improved sensitivity, enabling the observation of gravitational waves by the LIGO observatories.

    Another of Tony’s significant contributions was his invention of the unstable optical resonator—a conceptual advance that enabled high-power lasers with high beam quality. This configuration is the resonator of choice for lasers for which the lasing volume is large and the resonator length is small. In these systems, the unstable resonator allows a high-quality, near-diffraction limited output laser beam combined with efficient energy extraction from the laser medium. The technique allows excellent beam characteristics and discrimination against higher-order transverse modes. Uses of the unstable resonator have increased through the years, with applications to both medical devices and industrial processing.

    In addition to his groundbreaking technical achievements, Tony was an important contributor to education and leadership. His three textbooks—Microwave Solid-State Masers (McGraw-Hill, 1964), An Introduction to Lasers and Masers (McGraw-Hill, 1971), and Lasers—are standard references in the quantum optics literature, made especially valuable by his personal experience of having to learn quantum mechanics on his own after coming from an engineering background.

    Tony engaged enthusiastically with engineers and scientists around the world. He spent sabbaticals as visiting professor of applied physics at Harvard in 1965, Guggenheim Fellow at the IBM Research Labs in Zurich in 1969-70, and Humboldt Senior Scientist at the Max Planck Institute for Quantum Optics in Garching, Germany, in 1984-85.

    Siegman was director of the Ginzton Laboratory from 1978 to 1983 and again in 1998-99, and he served on numerous academic committees and as a member of the Stanford Faculty Senate and its Steering Committee. He served on the Optical Society of America Board of Directors (1976, 1997–2000), as OSA vice president and president (1996 and 1999, respectively), and he contributed to the OSA in numerous other ways as well.

    He received numerous awards and honors, including the Institute of Electrical and Electronics Engineers (IEEE) W. R. G. Baker Prize (1972) and the J. J. Ebers Award (1977). He received the Optical Society of America (OSA) R. W. Wood Prize (1980), the OSA Frederic Ives Medal/Jarus W. Quinn Prize (1987), and the OSA Esther Hoffman Beller Medal (2009). He was elected to the National Academy of Engineering in 1973, the American Academy of Arts and Sciences in 1984, and the National Academy of Sciences in 1998.

    After his retirement from Stanford, Siegman continued to travel to meetings and give invited talks, including a LaserFest presentation on masers and microwave cavities on the 50th anniversary of Theodore Maiman’s first ruby laser. He published on subjects ranging from fiber lasers to optics trivia. His interest in science and engineering continued unabated.

    Tony was always an outdoorsman. For many years, he and his wife would spend winters in their cabin near Lake Tahoe, where they would cross-country ski and hike.

    He is survived by his wife, Virginia “Jeannie” (née Howard), whom he married in 1974; his children, Winn, Patrick, and Anne; his stepdaughter, Elaine Lissner; and two grandchildren. He also leaves behind a legacy of generations of students and others he mentored who populate the field of optical science and engineering at Stanford and throughout the world and who carry with them the lessons and inspiration of a brilliant, rigorous professor and a modest, compassionate human being.

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    A valuable source for this tribute was Stephen E. Harris’ 2018 biographical memoir available on the National Academy of Sciences website (www.nasonline.org/memoirs). The NAS memoir provides more detailed technical discussion of Siegman’s work as well as a bibliography. This tribute also draws from Cynthia Haven. 2011. Laser pioneer Anthony Siegman dies at 79. Stanford Report; Jeannie Siegman and Thomas M. Baer. 2011. In Memoriam: Anthony E. Siegman (and attached tributes). Optica; and Stephen E. Harris. 2012. Anthony E. Siegman: Laser pioneer, Optical Society president, friend, and colleague. PNAS Retrospective 109(5):1379.