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Recognizing that nonlinear oxide-based
crystals can only shift the output of 1.06
μm (neodymium-based) and 1.55μm (erbium-based) solid-state lasers up to approximately 4
μm wavelengths, while chalcopyrite crystals suffer from low damage
thresholds and are not suitable for high-average-power
applications, researchers at BAE Systems (Nashua, NH)
and the U.S. Air Force Research Laboratory
(Wright-Patterson AFB, OH) have developed a new, robust
nonlinear optical crystal that generates mid-IR output
in the 2 to 9
μm range.
The high-optical-quality cadmium silicon
phosphide (CdSiP2) crystals—measuring 19 mm
in diameter and several centimeters in length—were grown
using directional solidification in a modified
high-temperature furnace. The unpolarized-absorption
spectrum of the crystal shows transparency between 560
nm and 9.5
μm.
This new crystal can be pumped with 1.06 or 1.55
μm
solid-state lasers to generate output beyond 4
μm
in a single optical-parametric-oscillator step; that is,
1.55
μm
pumping provides continuous tunability from 1.7 to 9.5
μm,
while 1.06 μm pumping produces a 6 μm output that could
be useful for medical applications.
Contact Peter Schunemann at
peter.g.schunemann@baesystems.com. |
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