Nicolaas
Bloembergen, a Dutch-born American physicist who studied quantum
mechanics by the light of an oil lamp while hiding from the Nazis in the
Netherlands in World War II and later shared a Nobel Prize for his
contributions to laser spectroscopy, died on Sept. 5 in Tucson, Ariz. He
was 97.
His death, at an assisted living facility, was caused by cardiorespiratory failure, his son, Brink, said.
Dr.
Bloembergen, who spent more than 40 years at Harvard University, was
considered the father of nonlinear optics, which investigates how
electromagnetic radiation interacts with matter.
In
the 1960s, physicists knew that ordinary light sources, like headlights
or lamps, were affected by the material with which they interacted. But
the newly created lasers were so powerful that they could transform the
very properties of what they passed through, creating newfound
phenomena and optical effects.
“He
was the first to realize and show that materials behave differently
when you have very intense beams of light falling on them,” said Jim C. Wyant, a professor emeritus at the College of Optical Sciences at the University of Arizona, who met Dr. Bloembergen in 1969.
An
analogy would be the striking of a tuning fork: When it is struck
gently, you hear a pure tone; but when it is struck hard, you hear the
harmonics. Similarly, when matter is struck with an intense enough laser
beam, you get a light harmonic, which is a nonlinear optical effect.
Dr. Bloembergen shared the 1981 Nobel Prize in Physics with Arthur Schawlow, a physicist from Stanford University, and Kai M. Siegbahn, of Sweden.
His
major contribution to the development of the laser was the creation of a
three-level pumping system, which made it much easier to pump atoms
from their ground state to a higher energy state, allowing the device to
operate continuously.
The
pumping scheme was originally designed for the laser’s predecessor, the
maser, which amplified microwaves instead of light. It offered a much
more practical and easier way of making lasers.
“He was one of the major intellectual forces in the explosion of science and applications related to the laser,” said John Armstrong,
a retired IBM research director who worked as a postdoctoral student in
Dr. Bloembergen’s lab in the 1960s. “There are a thousand applications
of lasers, not only in surgery but in all forms of manufacturing and all
forms of diagnostics for material properties.”
Before
his major advancements in nonlinear optics and laser development, Dr.
Bloembergen found early success as a pioneer in nuclear magnetic
resonance spectroscopy, a method of detecting the faint magnetism of the
atomic nucleus, which is used to study molecular structures and measure
magnetic fields.
His
doctoral thesis, “Nuclear Magnetic Relaxation,” explored what
controlled the shape of spectral lines, which can occur when atoms in
their excited state emit radiation. It was used to produce a paper
published in 1948 with his Harvard colleagues Edward M. Purcell and
Robert V. Pound that became one of the most cited works of physics and
was turned into a widely read book in the field.
“That was a giant contribution to spectroscopy that covers every field of science,” said Eli Yablonovitch,
a physicist at Berkeley who completed his doctorate under Dr.
Bloembergen. “The Nobel committee could have mentioned any of these
three things, or could have mentioned others, and it would have been
equally noteworthy.”
Nicolaas
Bloembergen, who was often called Nico, was born on March 11, 1920, in
Dordrecht, the Netherlands, the son of Auke Bloembergen, an executive at
a fertilizer company, and Sophia Maria Quint Bloembergen. He was the
second of six children.
Growing
up he yearned for academic challenges. At age 12 he attended a
prestigious municipal gymnasium in Utrecht, where he learned chemistry,
mathematics and Latin. But it was physics that he found most
challenging, and most worthy of pursuit.
He
graduated from the municipal gymnasium as valedictorian in 1938, giving
his speech in white tie and tails. Little did he know that he would
wear the exact same suit to accept, at 61, a Nobel Prize in Stockholm
many years later.
He entered the University of Utrecht to study physics. There, he took an experimental physics course with Leonard S. Ornstein,
who allowed him to assist a graduate student with his Ph.D. research
project. That led to Dr. Bloembergen’s first publication of a scientific
paper in 1940.
That same year Adolf Hitler launched a massive airborne invasion westward. Without warning, German troops parachuted into Holland and took control of the nation.
The
next year, Dr. Ornstein, a Jew, was removed from the university at the
same time that Jewish students were expelled. (Dr. Ornstein died six
months later from what Dr. Bloembergen had said was stress and
malnutrition.)
Though
Dr. Bloembergen was not Jewish, he was still a potential target for
deportation or even death; the Nazis were deeply suspicious that any
student could be part of the Dutch resistance.
Despite
studying under German occupation, he received the Dutch-equivalent of a
bachelor’s degree in 1941 and the equivalent of a master’s degree in
1943, mere weeks before the Nazis closed the University of Utrecht.
After graduating,
Dr. Bloembergen spent the next two years hiding from
the Nazis, including during the “hunger winter” of 1944, when food was
scarce and many died of malnutrition.
“I
remember eating bitter tulip bulbs to fill my stomach. They were hard
and indigestible despite of hours of boiling,” he wrote in his book, “Encounters in Magnetic Resonances: Selected Papers of Nicolaas Bloembergen.” “I read through the book ‘Quantum Theorie des Elektrons und der Strahlung,’ by H. A. Kramers, by the light of a storm lantern.”
The
Allied forces liberated Holland in 1945, and Dr. Bloembergen later left
the shambles of Europe for the United States. He enrolled in Harvard
and worked under Dr. Purcell on nuclear magnetic resonance. Dr. Purcell
would win the Nobel Prize in Physics in 1952 for his work with NMR.
Dr.
Bloembergen would go on to say that it was his good fortune to have
arrived at the lab six weeks after Dr. Purcell and his colleges detected
NMR in condensed matter. He had come upon a field that was ripe for
discovery.
Dr.
Bloembergen returned to the Netherlands to earn his doctoral degree at
the University of Leiden, in 1948, and defend his thesis.
While
there he met Huberta Deliana Brink, whom he called Deli. During the war
she had been in a Japanese concentration camp in Indonesia, where she
was born. Dr. Bloembergen returned to Harvard in 1949 and she followed
shortly after. They married in Amsterdam on June 26, 1950, beginning a
67-year marriage. Both became citizens in 1958. She survives him.
In
addition to his wife and his son, he is survived by two daughters,
Antonia Bloembergen and Juliana Dalton, and two grandchildren.
Dr.
Bloembergen became a professor at Harvard in 1951 and stayed there
until his retirement in 1990. He received the National Medal of Science
from President Gerald R. Ford in 1974. After retiring from Harvard, he
moved to Tucson and became a professor emeritus at the University of
Arizona, College of Optical Sciences, in 1991, though he would not
accept a salary.
In
2010, for his 90th birthday, his friends, family and scientists he had
mentored — the “Nicolettes,” as one colleague called them — gathered at
the university for an optical sciences symposium followed by a tennis
tournament.
“He was so well loved by colleagues and especially former students and postdocs,” Dr. Wyant said.
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