Photoionization Mode

A photoionization mode is a mode of interaction between a laser beam and matter, giving rise to a photoionization pattern, having very specific characteristics in terms of photoionization spatial distribution and density, as well as relative yields of photolytic species. A particular photoionization mode is also very specific in terms of the ultimate chemical and structural effects induced to a given dielectric material. The concept of photoionization mode refers to very distinct interaction regimes of a laser beam, normally a pulsed laser beam, with a dielectric material, which are governed by a specific set of laws, and controlled by a specific set of parameters. For this reason, this concept is very well defined.

We can identify four fundamental photoionization modes based on four fundamental optical effects, that give rise to four very distinct interaction regimes: single-photon mode (SP), filamentary mode (F), optical breakdown mode (OB), and below optical breakdown threshold mode (B/OB). Mixed modes are also possible.