PTB >> Q&A:
Thin-Disk, High-Power Lasers
The Who’s Who at NASA column in NTB’s January issue (available
on page 14 or online at www.techbriefs.com/whoswho)
discussed thin-disk, high-power lasers -- a key component of laser research
being led by NASA’s Marshall Space Flight Center (MSFC) in Alabama.
This month’s Q&A provides additional insight into this advancing
laser technology.
What are the advantages and applications of thin-disk laser
architecture?
One of MSFC's laser designs, the thin disk is based on original technology
developed by Dr. Giesen at the University of Stuttgart’s Institute
for Laser Research, in Germany (see illustration). The small-volume large-area
gain medium, or thin disk, design shows considerable promise for high
efficiency, compact, and lightweight laser packages, which have the qualities
and high power of much larger and more cumbersome laser systems.
This thin-disk technology has recently been incorporated into commercial
industrial welding and cutting equipment, demonstrating the efficiency
and robustness of the technology. The elegant pump cavity design leads
to more output beam efficiency with an overall reduction in the system-level
power requirements, which may prove ideal for power beaming and space
applications.
One of our current research objectives, for instance, is to develop, build,
and test a multi-kilowatt solid-state laser suitable for space applications
using thin-disk technology, and to demonstrate optical power transmission
over a distance. We are supporting this development with a variation of
gain materials and pump methodologies to support the development of high-power,
space-qualified lasers with the ability to be scaled to many tens of kilowatts
in a compact and lightweight package. These technologies possess the potential
to produce viable high-power laser systems in the shortest amount of time.
This technology can also be packaged into extremely compact low power
output (a few tens of watts) lasers for use in such applications as might
be envisioned on the International Space Station, or for other microgravity
or space research.
This technology effort may also eventually produce laser devices capable
of providing on-orbit propulsion and planetary exploration power. Thin-disk
lasers may reduce the cost of such efforts by reducing the amount of fuel
necessary to be carried on the vehicle, or possibly provide the vehicle
with a virtually unlimited operating life without fuel limitations.
The development of ultrastable lasers may also be facilitated by this
work. Ultrastable lasers will enable missions requiring long distance
measuring or pointing capability (such as in a free flyer or formation
flying concept), and scenarios requiring the use of compact, lightweight,
and highly efficient lasers (such as deep space communication or power
transmission missions).

Tim Blackwell is an advanced laser systems engineer for the University
of Alabama, located at the National Space Science and Technology Center
(NSSTC) in Huntsville, Alabama. He can be contacted at Timothy.S.Blackwell@nasa.gov
or (256) 961-7036.
The NSSTC is a research partnership between NASA's MSFC, Alabama universities,
federal agencies, and industry. Visit www.nsstc.org
for more information.
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