77th Annual Meeting of the Southeastern Section of the APS
Volume 55, Number 10
Wednesday–Saturday, October 20–23, 2010;
Baton Rouge, Louisiana
Session HB: 50 Years of Solving Problems in Science, Technology, and Medicine with Lasers
1:30 PM–3:30 PM,
Friday, October 22, 2010
Nicholson Hall
Room: 109
Chair: John Thomas, Duke University
Abstract ID: BAPS.2010.SES.HB.1
Abstract: HB.00001 : Simple Devices for Measuring Complex Laser Pulses
1:30 PM–2:00 PM
Preview Abstract
Abstract
Author:
Rick Trebino
(Georgia Institute of Technology)
Shortly after the development of the first lasers, researchers
learned a valuable lesson: lasers were not very useful if their
beam spatial quality was poor. Fortunately cameras could measure
the beam quality, which then rapidly improved.
Just as lasers must be smooth and stable in space, they must also
be so in time. Fortunately, electronic detectors and
oscilloscopes could measure the laser intensity vs. time. Until,
that is, researchers began to generate pulses nanoseconds and
even picoseconds long, too fast for these devices.
It was not until pulses reached fs lengths that complete
intensity-and-phase measurements became possible.
Frequency-Resolved Optical Gating (FROG) nicely solved the
problem, yielding the pulse intensity and phase vs. time for
arbitrary fs pulses. Additional simple techniques can measure fs
pulses' complete intensity and phase vs. time and space. Indeed,
fs light pulses are now arguably the best characterized type of
light, and they are the basis of ultrastable metrology.
But what about ns pulses? In the process of opening up new
regimes of science, the measurement of much longer---and far more
common---intermediate length pulses was forgotten. As a result,
ns pulses from Q-switched solid-state lasers, pulsed diode
lasers, and high-power fiber lasers and amplifiers are often far
from ideal in time and no one knows precisely what
their distortions look like. Yes, electronic detectors and
oscilloscopes have become faster, but such exotic devices are
expensive and fragile and only yield the intensity and not the
phase. Measuring ns pulses has proved much more difficult than
measuring fs and ps ones.
Happily, we have recently demonstrated a novel FROG for measuring
ns pulses. The main challenge was generating a ns delay range on
a single shot, a problem we solved in a novel manner: by tilting
the input pulse by 89.9 degrees.
This novel device completes the many-decades-old task of
developing simple techniques for measuring essentially all laser
pulses.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.SES.HB.1