The ablation method is fundamental for laser micromachining. Conventional pulsed-laser machining processes dissociate matter at atomic and molecular levels by application of laser radiation. The absorbed laser energy is passed to the material’s atomic and molecular lattice, which induces ablatement of the substance. Simultaneously, this energy is ultimately transformed into heat that disperses out of the laser spot volume beyond the laser pulse duration.
However, surgically clean and extremely localized laser ablation is possible without significant damage or alteration of the underlying material, by using femtosecond laser micromachining. Femtoseconds are the time-scale in which a process called cold ablation can develop.
The principle of cold ablation is an ablation that happens in the process of femtosecond laser absorption, during the athermal state of the substance. The aim is to remove excess material before it is in a state of total thermal equilibrium, allowing it less chance to create heat that will migrate away from where directly absorbed laser energy.
The material’s athermal ablation and thermalization happen simultaneously, unlike digitally turning it on or off in the time. This makes the time for the cold, athermal, or thermal ablation largely overlap each other at various degrees of weights. Moreover, heat build-up and dispersion can happen in parallel, which moves the heat out of the laser-spot volume by the electron subsystem and atomic or molecule lattice methods.
Fast repetitive laser pulses are utilized to ablate material to increase the ablation rate, which adds further difficulties in almost all practical cases. This often reaches a significantly elevated temperature in the material. The temperature is, however, not necessarily high enough for ablation, but it can melt down the solid-state material. So perfect material ablation demands modern femtosecond laser micromachining systems, applications, and expertise.
Laserod Technologies is one of the industries’ leading experts in laser micromachining of polymers and other substrates for- microscale applications. Our high pulse- femtosecond laser micromachining is uniquely suited for microscale-polymer machining for many applications. Contact Laserod Technologies today at 1-888-991-9916 / 1-310-340-1343 for projects and inquiries!