CO2 Lasers
The CO2
laser is a gas laser where the
active medium is carbon dioxide (CO2). Typically a mixture of
carbon dioxide, nitrogen (N2) and helium (He), the
laser
gas is excited by high-voltage or
high-frequency and circulated at high velocity inside the
resonator. The resulting laser light has a wavelength of
10.6um (infrared range); the beam is transferred to the point
of use through mirrors and lenses.
New developments in the
field of CO2 lasers have led to the introduction of “Diffusion
Cooled” laser resonators; these units are characterized by a
compact design, the absence of forced gas circulation and
reduced resonator gas usage. On the other hand, these types of
resonators use a gas mixture with a higher degree of
sophistication, requiring up to 6 components and often
involving carbon monoxide (CO) and xenon
(Xe).
Since they are
commercially available at power levels up to 40kW, CO2 lasers
are widespread in the industry, especially in applications
requiring power levels of 2-12kW like:
- Laser cutting
- Laser welding
- Laser surface
treatment
In order to
guarantee a flawless operation of the resonator, gas purity is
critical. With the quantity of optical components built into
the resonator typically increasing with power levels, the
effects of contaminated gases can lead to tremendous costs.
Especially the levels for moisture (H2O)and hydrocarbons (THC)
must be closely controlled; the competent laser gas supplier
will ensure quality standards through the use of high purity
base products and thorough filling procedures.
Further, in order to ensure that the cylinder’s
high gas quality reaches the resonator, special attention has
to be paid to the choice of gas
supply equipment, like pressure
regulators, hoses and fittings. |
