Multiphoton Optics’ technology uses ultra-short pulsed laser light as manufacturing tool. The technology is based on a two- or multiple photon absorption (TPA / MPA) process in case of additive fabrication, initiated by ultra-short laser pulses. Due to the nature of the non-linear process, the intensity is only high enough to initiate a reaction in a material in the strongly confined focal volume. The method is known as High-Precision 3D Printing on a sub-micrometer scale, where structures are created in the additive mode in photo-responsive materials such as polymers, hybrid polymers, or special glasses.
Dependent on the underlying material to be processed, this confinement cannot only be used for additive, but also for subtractive fabrication. A large variety of different materials can be processed by making use of the specific nature of the processes enabled by a femtosecond light source, also allowing to create structures in metals with very high precision.
In principle, the focal volume which is defined by the technical equipment and the optics determines the size of a created voxel (volume pixel) to a certain extent. However, the reaction kinetics of the underlying materials and other processes such as threshold processes related to the material composition also play a crucial role for the minimum size of a resulting voxel enabled by a material. This means that different interaction volumes have to be considered. While the technical interaction volume (red voxel) which is determined by the employed optics, by the stability of the laser, and by the stability and accuracy of the positioning system can be easily optimized, the chemical interaction volume (green voxel) is much more difficult to minimize, because this is dependent on many different factors such as, for example on the reaction kinetics of the material formulation and, consequently, on the laser-light initiated propagation and termination reactions in a material.