Laser Cutting Theory
A cross-section of a laser’s beam profile is commonly referred to as mode. Described in terms of TEM (Transverse Electromagnetic Mode) mode relates to the beam’s ability to be focused. It is also comparable to the degree of sharpness of a cutting tool. The lowest order or reference mode is TEM00, of which the beam’s profile simulates a Gaussian distribution curve. Modes which approach this energy distribution can be focused down to the laser’s theoretical minimum spot size and give the sharpest energy density.
Higher order or multi-mode beam profiles are characterised by a tendency to spread out the energy distribution away from the centre of the beam. The resultant spot is large with this mode causing lower energy concentration. Therefore, higher order mode lasers are considered to be duller cutting tools than low order mode lasers of equivalent power output.