There is a problem that some lasers do not cut or engrave on different materials, for example, metals, glass, plexiglass.
An explanation is very simple – different materials absorb and reflect different wavelengths, therefore, more power is absorbed – easy cutting or engraving will be. More power is being reflected – less power will achieve the surface.
Under this plot you may see that Al, Ag, Au, Cu reflect almost all wavelengths after 1000 nm.
Based on Researchgate data you may see that aluminum absorbs wavelength shorter than 100 nm and almost does not of other wavelengths, has a small spike somewhere 850-900 nm.
For example, gold and silver are kind of sensitive to the wavelength 300-500 nm.
As you may see steel and pure iron are sensitive to wavelengths more than 1050 nm. which is why most fiber lasers for metal cutting use 1064 / 1080 nm wavelength.
This Data is For a Copper Standard Solution And Bears No Resemblance To Elemental Copper Metal
This Plot Shows Substantial Copper Absorption (About 43 %) at 450 nm
According to Keyence’s research, you may see that all metals except aluminum have downslope after 450 nm.
Why it is impossible to engrave or cut with lasers of wavelength more than 300 nm
As you can see on this chart almost all types of glass are transmitting all wavelength longer than 300 nm
Glass cutting is possible with the laser with a wavelength of more than 4.4uM (4400 nm)
The regular glass absorbs wavelength longer than 4000 nm (4 uM) which is far-infrared, that is why laser cutting of glass and acrylic can be don on Co2 lasers with a wavelength of 10.6 uM.
Acrylic transition coefficient
Window glass transition coefficient
Different types of glass transmission rate
Reflection rate in percentage (%) from a polished surface.
Types of wavelength
The wavelength, А (10A=1 nm)
Steel (1% С)
PVC absorption coefficient
Transmittance for: Polystyrene, cyclic olefin polymer, polycarbonate, PMMA, UV acrylic
PET plastics transmittance ration
PLA plastics absorption coefficient
Wood reflectance and absorption coefficients