Thermal Limitations in Ultrafast Laser Direct Writings in Dielectric Solids

In the context of an ultrafast laser interacting with solids, temperature plays a special role in the transformation processes. Some of these processes can be thermally activated, while others can be either solely driven or constrained by temperature-such as refractive index change (fictive temperature), nanopore erasure, micro-bubble formation, and phase transition-like crystallization. The objective of this paper is to use a recently developed analytic approximation to understand the limitations imposed by the spatial temperature distribution and its evolution over the writing time, based on the key laser parameter combinations, and subsequently determine the boundary conditions of these parameters.