Meyer and his colleagues at Iowa State,
Spectral Energies LLC and the U.S. Air
Force Research Laboratory (AFRL) built
the system around a narrow-linewidth
pulsed fiber laser as the master oscillator. The researchers used an electro-optic
modulator in a burst-mode laser to reduce
unwanted amplified spontaneous emission. Finally, the system relied on diode-pumped solid-state amplifiers instead of
flashlamp-pumped amplification; the
former has about 10 times the efficiency
of the latter, according to Meyer.
To demonstrate what the laser system
can do, the team performed planar
laser-fluorescence imaging of a mixture
of formaldehyde in a methane-air flame
illuminated by the laser. At that time,
the system was still using a combination
of diode-pumped and flashlamp-pumped
amplifiers. The researchers caught
10-ms-long, 200-image sequences with
Iowa State Univ., Spectral Energies LLC and the U.S. AFRL
10-ms sequence showing the combustion of
formaldehyde in a methane-air environment.
laser pulse energy of up to 150 mJ at
1,064.3 nm, as reported in the Optics
Letters paper. Since submitting the
article, the researchers switched the
remaining flashlamp-pumped amplifiers
to their diode-pumped counterparts and
realized 30-ms-long sequences.
Any kind of gas-phase spectroscopy
would benefit from this type of burst-mode laser, says Meyer. It also could
be used to pump an optical parametric
oscillator to study other types of intermediate chemical species in the combustion process.
Meyer’s team included Mikhail
Slipchenko and Sukesh Roy of Spectral
Energies, James Gord and Stephen Danc-zyk of AFRL and Iowa State doctoral
student Joseph Miller.
ONLINE EXTRA: Visit www.osa-opn.org for weekly news updates.
Patricia Daukantas ( email@example.com) and
Yvonne Carts-Powell ( firstname.lastname@example.org) are
freelance science writers who specialize in
optics and photonics.
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