This year, the Nobel Prize in Physics was awarded to three
individuals for “groundbreaking inventions in the field of laser
physics”: Arthur Ashkin with Bell Laboratories in the United States;
Gerard Mourou of the École Polytechnique, Palaiseau, France, and the
University of Michigan, Ann Arbor; and Donna Strickland from the
University of Waterloo in Canada.
Steve Smith, who earned his Ph.D. doing research in a National
Science Foundation Science and Technology Center directed by Mourou at
the University of Michigan, was pleased to hear Mourow was receiving a
share of the Nobel Prize.
“It’s nice he received a part of this prize. But it also gives
acknowledgement to a lot of people in different areas of laser physics.
That’s usually how it works—one person gets the prize but there are
hundreds of people doing similar work that is very impactful, and this
elevates their research as well,” said Smith, who is a professor and
director of Nanoscience and Nanoengineering at the South Dakota School of Mines & Technology (SD Mines).
At Deep Talks: Nobel Day,
Smith will discuss the topics relating to this year's Nobel Prize in
Physics, including Mourou’s work in the field of laser physics and how
it has impacted a variety of scientific and technological applications.
He and students will also have some optical science demonstrations to
interact with. The event takes place Thursday, Dec. 13, beginning at 5
p.m. at the Sanford Lab Homestake Visitor Center in Lead.
Mourou and Strickland shared ½ of the Nobel Prize for their work in
the area of high-powered, ultra-fast lasers, in which they developed the
“chirp pulsed amplification (CPA)” method.
“It’s really the concept of stretching laser pulses out in time,
amplifying them, and then compressing them in time,” Smith said. “The
technology allowed scientists to develop intense laser sources that have
been used for laser eye surgery, for communication technology, for
precise measurements of time, for generating coherent x-rays, and for
fundamental studies of the behavior of matter under extreme conditions.”
Ashkin, on the other hand, invented optical tweezers that grab
particles, atoms, viruses and other living cells using light. According
to the Nobel Academy, “this new tool allowed Ashkin to realize an old
dream of science fiction—using the radiation pressure of light to move
physical objects.”
Ashkin’s discovery allows scientists to study the mechanical properties of single molecules, including DNA.
Smith was a Ph.D. student when he began working in the Center for
Ultrafast Optical Science, directed by Mourou, and was able to be
involved in some of the groundbreaking research into ultrafast laser
science and technology Mourou and others were engaged in at the time.
“Mourou’s group concentrated on generating ever more intense laser
pulses with higher and higher energies, approaching PetaWatts (10^15
joules per second). That has since been exceeded,” Smith said. “It was
said that a PetaWatt was roughly equivalent to the peak electrical power
required in the entire United States during a work day (9-5). That’s a
lot of power!”
Of course, that amount of power existed for a very short amount of
time—one millionth of one billionth of one second (or a femtosecond),
meaning the total energy created is just one joule, which is not a lot
of energy.
“A light bulb, for example, burns 100 joules every second. However,
in that very short period of time, the intensity created by the laser
pulses is so high it causes matter to behave in very unusual ways,”
Smith said. “The electrons can be accelerated to relativistic speeds,
generating x-rays as a consequence.”
Smith’s work as a Ph.D. student combined ultrafast lasers with
nanophotonics. “Gerard focused on building and developing high-powered
lasers; my group focused on using the lasers to do science. My pulses
were much weaker than his—we were sort of like David and Goliath.”
Mourou squeezed photons in time whereas Smith’s efforts centered on
squeezing photons in space as well, Smith said. “We wanted to use these
photons as a kind of nanometer strobe light. We wanted to ‘see’ what
electrons inside semiconductors were doing and how it affected the
properties of devices like transistors as they got smaller and smaller,
where quantum mechanical effects become important.”
Smith said the work is important to future technologies, which could
lead to smaller, more compact and more powerful electronic devices.
New technologies include coherent x-rays, which were generated by
ultrafast lasers for use in nano-scale imaging in the STROBE center,
headed by Margaret Murnane at the University of Colorado, Boulder; and a
high-power laser system similar to Mourou’s, built by Don Umstader at
the University of Nebraska-Lincoln, to study high temperature plasmas
and other so-called high-field phenomena.
Smith’s research at SD Mines focuses on optics, using
photonic methods to image live cells, and to understand the light matter
interaction in a nanostructure that could lead to finer scale,
all-optical circuits, sensors and energy devices.
“All materials interact with light—that’s why we can see colors,”
Smith said. “The interaction of light with materials helps us understand
the properties of matter. That’s what my research is all about—the
nature of that interaction.”
But what really gets him excited is his work with students and other faculty members.
“We are doing new and novel imaging experiments that are seeing
things no one has ever seen. It’s exciting to see their accomplishments
and to share a bit of what I’ve learned,” Smith said. “One of the nice
things about teaching is that you get to keep being a student—you learn
all the time. That’s one of the most exciting things about teaching.”
Written by Constance
Walter, Sanford Underground Research Facility.
See article here.