Currently, there are several design types of CO2 laser, which sometimes overlap in terms of their construction. The most common design types are the longitudinal-flow and transverse-flow lasers, the sealed-off laser, the waveguide laser and the TEA laser.
Longitudinal-flow and transverse-flow lasers
This design is comparatively simple and most often used with high output lasers. In longitudinal- and transverse-flow lasers, a laser gas is continuously vacuumed through a discharge tube by using a vacuum pump. By means of a direct current discharge, a portion of the carbon dioxide contained in the gas mixture is split into carbon monoxide and oxygen. By the means of several pumps in the tube system, the gas mixture is continuously circulated, enabling a more efficient removal of heat loss..
In this design, instead of the gas mixture being replaced by a circulating pump, hydrogen, water vapour and oxygen are added to the gas mixture. These added gas mixtures ensure that the resulting carbon monoxide reacts via an electrode made of platinum to carbon dioxide. CO2 is therefore catalytically regenerated.
The waveguide laser, also known as a slab laser, uses two electrodes as waveguides and has a cuboidal resonator. As the cross section has a high aspect ratio (e.g. height to width 10:1) the resonator has a relatively large surface area compared to the volume. This enables the efficient removal of heat loss.
The “transversely excited atmospheric pressure laser”, TEA for short, is always used when high gas pressures up to one bar are required with pulse durations up to 100 ns. In this design the discharge voltage is applied in short pulses of under one microsecond across the gas flow. This prevents arcing.