Nicolaas Bloembergen, a Dutch-born US physicist and Nobel laureate, died from cardiorespiratory failure on 5 September 2017 in Tucson, Arizona. Generally regarded as the father of nonlinear optics, Nico will be remembered not only for his groundbreaking scientific achievements but for his great perseverance and genuine concern for others.
Born in Dordrecht, the Netherlands, on 11 March 1920, Nico grew up in Bilthoven, a residential suburb of Utrecht. His innate curiosity about the correspondence between mathematics and physical facts led him to study physics at the University of Utrecht. He received his bachelor’s degree in 1941 and completed the equivalent of a master’s degree in science in 1943; he passed his doctoral qualifying exam just three months before the university was closed later that year by German forces occupying the country. For the remaining two years of World War II, everyday liberties were greatly restricted, forcing Nico to hide indoors most days. During the winter of 1944–45, known as the Dutch Hunger Winter, Nico’s family ate tulip bulbs to survive, and at night, using a storm lamp, Nico read Hendrik Kramers’s book on the basics of quantum theory.
Nico always thought he would start work on his PhD thesis outside the Netherlands. Because of Europe’s devastation, in 1945 the US seemed to be the most promising place to conduct research. At the suggestion of his older brother, Nico applied to the University of Chicago, which never replied; to the University of California, Berkeley, which wrote that it was not admitting foreign students at the time; and to Harvard University, which accepted him after receiving additional recommendations.
Luckily for Nico, he arrived at Harvard six weeks after Edward Purcell, Robert Pound, and Henry Torrey had detected an NMR signal in condensed matter. He was hired as a graduate assistant to develop the early NMR device. “The hitherto unexplored field of nuclear magnetic resonance in solids, liquids and gases yielded a rich harvest,” Nico wrote in his biographical Nobel sketch. That research resulted in his 1948 Physical Review paper with Purcell and Pound, now commonly referred to as BPP, which became one of the most-referenced physics papers ever.
Nico returned to the Netherlands in 1947 to submit his PhD thesis, “Nuclear magnetic relaxation,” at the University of Leiden. After receiving his degree in 1948, Nico worked as a postdoc for Cornelius Gorter at the Kamerlingh Onnes Laboratory for a year, and then he returned to Harvard to join the Society of Fellows. Although Nico also studied nuclear physics and microwave spectroscopy at the Harvard cyclotron, he ultimately chose to work on smaller-scale spectroscopy experiments.
In 1956 Nico created the crystal maser, which grew out of his work in microwave spectroscopy. In the early 1960s, soon after Theodore Maiman unveiled the laser, Nico extended his spectroscopy work into tunable lasers and developed a high-precision technique to observe atomic structure. His work on laser spectroscopy in turn led to his conception of nonlinear optics, in which he created a new theoretical way to analyze how electromagnetic radiation interacts with matter. “In fact, what we did was quite simple,” Nico told the Dutch newspaper de Volkskrant in 1990. “We took a standard textbook on optics and for each section we asked ourselves what would happen if the intensity was to become very high. We were almost certain that we were bound to encounter an entirely new type of physics within that domain.”
Nico became an intellectual force at Harvard and rose quickly through the academic ranks. He became an associate professor in 1951 and received named professorships in 1957, 1974, and 1980. Nico retired from Harvard in 1990 as Gerhard Gade University Professor Emeritus.
Among the many honors Nico received for his work were the American Physical Society’s 1958 Oliver E. Buckley Prize for Solid State Physics and the 1974 National Medal of Science. In 1981 the Nobel Prize in Physics was awarded to Nico and Arthur Schawlow for developing laser spectroscopy and to Kai Siegbahn for developing high-resolution electron spectroscopy.
Despite receiving such impressive honors, Nico continued to dedicate himself to teaching and mentoring. Throughout his life, he retained an attitude of sincere modesty. Harvard professor Eric Mazur, a postdoc of Nico’s, recently said of his mentor, “Even though he received the Nobel Prize … he always remained one of the humblest people I have ever known… . He considered the success of the people around him his biggest accomplishment.”
John Armstrong, a retired IBM vice president of science and technology, also worked in Nico’s lab. He recalled the profound influence Nico had on his career: “It was the formative experience in my life as a scientist to have worked with him in [nonlinear optics] as a postdoc. He provided crucial support at an early stage in my career, and I believe this was true for many of his former students and postdocs.”
Nico remained active at Harvard until he and his wife moved to Tucson in 2001. He was appointed as a professor of optical sciences at the University of Arizona. Refusing a salary, Nico was given an office, a computer, and a parking spot next to the optical sciences building. As only an academic could appreciate, the nearness of the parking space was the most important part of the arrangement.
For his entire scientific career, Nico kept his high level of productivity and enthusiasm for science. Until his health started to decline during the last year of his life, he went to his office several days a week. He welcomed any opportunity to meet with visitors, students, and faculty. His standing in the optics community and the respect he inspired were evident at his 90th birthday party in 2010. In addition to the many former PhD students and postdocs who came to celebrate their mentor, Nobel laureates Roy Glauber, John Hall, and Charles Townes attended. Loved by many for his generosity, playfulness, and kindness, Nico will be greatly missed.
