The Physics: how it worksThe illustration on the left shows the effects of laser cleaning. The grey layer on top op the base material is the contamination. This layer will absorb the laser energy very well, whereas the base material (steel, aluminum, wood, plastics...) will reflect most of the energy.
The laser is short pulsed, this means that the laser beam is comparable to small bullets of light, shooting at a frequency of around 200.000 pulses/second!
When a bullet hits the absorbing layer, two things can happen:
The base material stays cold, while the absorbing layer heats up.The heat-expansion difference will cause the contaminant to crimp off the base material.
The contaminant heats up that much, a plasma is created around the working area. This will cause evaporation.