Lithography is a method of printing that uses flat plates rather than etched or carved plates or die sets.
This has traditionally be performed using hydrophobic and hydrophilic substrates to attract and repel inks, however modern methods – offset lithography – uses flat flexible plates coated with photosensitive emulsions.
A negative image is created on the emulsion by contact with the original design and then exposing the plate to a light source. This can also be achieved by shining UV light through a negative onto the printing surface which has been coated with a chemical that allows an oil based ink to bind to it.
Lasers however can be used to directly create the image in a number of different ways. Thermal plates use high pulsed lasers, whilst polymer and silver halogen plates require lower energies in the 400-700nm wavelength range. It is important that the power output from the laser is stable to avoid differences in image intensity. Additionally, high pointing stability will ensure the created image is sharp.
The gem lasers are ideal for these applications as they have excellent stability ensuring consistent printing results of equal intensities and are small, enabling them to be easily integrated into the instrument.