Higher
Power Green (532
nm) Laser
U.S. Laser Corp. offers a new level of
performance for frequency-doubled Nd:YAG lasers: 6 watts (average power @ 5 kHz
Q-switch freq.) of TEM00 output at 532 nm.
Background and Problem
To produce laser energy at 532
nm, a second harmonic generator (SHG) crystal is used to convert the fundamental
Nd:YAG wavelength (1064 nm). Maximum conversion efficiency is achieved when the
crystal is placed intracavity since the 1064 nm radiation is allowed to pass
through the crystal multiple times. Of the converted energy, roughly 50% exits
the crystal towards the front mirror, where it leaves the resonator and is
available to the user. The other half exits the crystal towards the laser rod,
where it is absorbed. If this absorbed energy could instead be directed out of
the laser resonator, it could become available to the user, thus increasing the
total available energy.
Solution
As shown in the figure above, a
special dichroic mirror is placed between the SHG crystal and the laser head.
The coatings on this mirror are designed to have high reflectance at 532 nm,
with minimal insertion loss at 1064 nm. The reflected energy is directed (with
the kinematic adjustments) out of the front mirror. A key feature of this
solution is that the increased power is achieved with no increase in 1064
circulating power; thus there is no increased risk of coating damage to the
crystal or mirror. (Alternatively, this configuration can be used to reduce the
circulating power required to produce a given 532 power, reducing the risk of
damage, and extending lamp life).
Availability
This 'three mirror' configuration is a part of
U.S. Laser's Model 403TQG3 laser. A field installable upgrade for Model 403TQGH
is also available. The upgrade consists of the dichroic mirror in a kinematic
rail mount, SHG crystal mounted in a cell, and front mirror. All optical
elements have advanced high damage level coatings.
U.S. Laser Corp. is
the leading U.S. manufacturer of Nd:YAG lasers and laser systems for industrial
materials processing. We offer the widest range of output powers (from 7 watts
TEM00 to >2000 watts), plus Q-switched, frequency doubled and
quadrupled models. Our beam delivery systems (conventional and fiber optic) are
state-of the-art in beam quality and transmission, and feature integrated
coaxial CCTV viewing. We can provide standard and custom turnkey systems for
welding, cutting, scribing, trimming, soldering, and specialty applications. Our
fully equipped laser applications lab is available for demonstration and process
development.
For more information,
contact sales at (201)848-9200, [email protected]
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