OPN Talks with …
Gérard Mourou
CPA Inventor and CLEO 2010
Keynote Speaker
Gérard Mourou of France’s École Polytechnique and the Institut de
la Lumière Extrême at ENSTA (École
Nationale Supérieure de Techniques
Avancées) has an impressive history with
lasers. In addition to his research contributions in the fields of ultrafast lasers,
high-speed electronics and ophthalmology, Mourou invented the technique
known as chirped pulse amplification
(CPA)—which enabled the generation
of extremely high laser intensities and
opened a new branch of optics called
relativistic optics. Mourou will be one
of the plenary session keynote speakers
at CLEO/QELS this year in San Jose,
Calif., U.S.A., from May 16-21.
well-defined state, which has led to all
the new applications of the laser that we
know today.
“I like to work with students who have fire
in their bellies. Those
who have passion are
highly motivated but
also have independent
minds.”
Lasers are notorious for their poor
efficiency—on the order of 1 percent
or less. There is an exception with the
diode-pumped laser, where a wall plug
efficiency of approximately 50 percent
has been demonstrated. However, applications need to be more efficient.
Over the past 50 years, what
has been the most significant
advance in lasers?
In terms of how lasers can be used, I
would say that gaining the ability to control the laser has been the most important breakthrough. The laser produces
light in a well-defined state, characterized by a specific frequency, amplitude,
polarization and direction. Acting on
these parameters, we can now project the
light from a well-defined state into a new
How do you see the laser and
its uses evolving in the next
50 years?
I see the laser evolving along the lines
of guided wave optics. Progress in this
area is so impressive, thanks to the
work of Charles Kao, one of our newest
Nobel laureates. Now we can generate,
amplify, transport, shape and control
large amounts of power. The only thing
we can’t do yet is generate and propagate large amounts of energy per pulse
with fibers. To do that, we need to
phase large quantities of fibers.
Have there been any uses of
chirped pulse amplification that
have surprised you?
Yes. The one application that most
surprised me is its use in micromachining. You see, when you machine with
femtosecond lasers, it is completely
different than when you do the same
operation with 100-ps pulses. The material removal is extremely clean, absent of
collateral damage. This is true in metals
and transparent dielectrics such as the
cornea. You can precisely machine the
interior of transparent materials. When
I saw that, it was a shock for me—a
real epiphany. This is what gave birth to
femtosecond ophthalmology. Before, it
was performed with lasers pulsing at tens
of picoseconds and, quite frankly, it did
not work. In order to make very clean
cuts to the tissue, you need to be in the
femtosecond regime.
12 | OPN Optics & Photonics News
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