It is commonly known that laser beam is suitable for cutting of paper materials. Even tough laser technology has been applied to paper material cutting since 1970’s; there exists quite a few published research results about issue.
Purpose of this literature review is to give comprehensive point of view about interaction between laser beam and paper materials by examining the issue from different aspects:
Optical phenomena of interaction
Absorption phenomena of interaction
Thermo-chemical phenomena of interaction
When realized that paper materials is a miniature 3D net structure consisting fibres, pores and small pigment particles, it can be foreseen that there are many optical boundaries and surfaces inside material that seems to have even smooth surface for outside observer. Actually paper is optically much more complicated than a metal surface. That is why interaction of laser light can be transmitting, reflecting, scattering, refracting, diffracting, absorbing etc., when it interacts with paper material and the phenomena happens both on surface and inside the structure.
There exist only a few articles about the absorption of laser beam to paper materials. The problem of these articles is that they concentrate in visible wavelength range and usually the used power is low. Based on literature, it was found that paper materials have absorption maximum in wavelength ranges of around 3 µm and 8-10 µm.
It is also important to understand what happens to paper material at high temperatures. Chemical mechanism of thermal decomposition of cellulose (basic component of paper materials) in laser processing is called pyrolysis; solid cellulose decomposes at high temperatures and in absence of oxygen into small volatile compounds, like COx, water and furanes.