Temporal measurement of CO2 laser output resolved into transverse direction, polarization components and rotational transition.

Measurement of the temporal behaviour of laser beam properties like total beam power, intensity distribution, polarization or frequency can be necessary for a better understanding of laser dynamics as well as processing results in laser material working. In this paper, we report on the measurements with a linear 12-segment array of pyroelectric detectors, which allow parallel registration of the detector signals with a bandwidth of 1 MHz. Although the relevant time constants of the thermal processes in CO2 laser material processing in many cases are greater than the time constants, we are reporting here, knowledge of the temporal behaviour of the laser beam parameters can be important for special applications, e.g. precise material working with small workpiece dimensions. Pulse modulation capability, e.g. by pump power modulation, increases the flexibility of a laser source, but disregarding laser dynamics can lead to undesired processing results or failure of processing.