Specifications

Beam Delivery
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one-way valves in the beam delivery system to allow excess purge
gas to leave when the axes contract. For very high-speed systems, it
may be necessary to have the purge gas flow switch from a normal
rate to a higher rate when the axes extend.
Polarization
Diamond lasers have a highly polarized output. The direction of
polarization is horizontal for all Diamond lasers but the K-400 and
K-500, where it is vertical. In some applications, notably ceramic
scribing and metal cutting, superior results are achieved with
circular polarization. A quarter wave plate is required to convert the
linear polarization to circular. For high-power CO
2
lasers, reflective
optics are generally used as wave plates. Such optics must be set to
reflect the beam at 45º to the direction of polarization of the
incoming beam. The Coherent CQE module, Part Number
5701-0059, (Figure 11) allows this to be done easily.
To preserve circular polarization, all beam bending mirrors after the
CQE must be “zero phase shift” optics. Despite their name, these
optics typically have up to 6° of phase shift each, so it is best to put
the CQE near the process end of the beam line to avoid loss of
circular polarization.
Back Reflection
High power laser systems are very sensitive to light reflected back
from the work or from support tooling. If, for example, cloth is cut
on an aluminum backing plate, a large fraction of the laser power
will be returned through the beam delivery optics. This light is fairly
well-collimated by the focusing lens and can enter the laser cavity
with possibly catastrophic effects. Even if laser damage does not
Figure 10. Cross Section of Air Ejector for Protecting Bending Mirror