Process diagnosis

 

Task

Expulsion of melt after an aluminum sample was irradiated with an ultrashort laser pulse. Expulsion of melt after an aluminum sample was irradiated with an ultrashort laser pulse.

When using ultrashort pulsed laser radiation for material processing, classic models for the description of light-matter interaction are no longer valid due to the large intensities. In order to optimize the ablation quality and efficiency, a complete understanding of the interaction and absorption processes is absolutely necessary. A variety of theoretical models describing the light-matter interaction are developed for the last decades that aim to describe the interaction processes completely and correctly. Almost all models make fundamental assumptions and so neglect effects that may play a significant role for the interaction process. One experimental approach to analyze and understand the interaction process is the direct in-situ observation of the process with time-resolved measurement methods.

 

Process

At the chair of laser technology LLT two different methods are used to investigate the process dynamics. They are described in detail under the following links:

Femtosecond pump-probe microscopy

Nanosecond ICCD Photography

Furthermore, ex-situ absorption measurements of solids such as graphite irradiated by ultrashort laser pulses can be performed, which is described in detail under the following link:

Absorptiometry

 

Main topics

Below, some topics in the field of process diagnosis of the group Ultrashort Pulse Processing are shown:

  • Investigation of the formation dynamics of ultrathin graphite following excitation of ultrashort pulsed laser radiation
  • Temporal evolution of free electrons while processing glass
  • Pulse-to-pulse interaction during materials processing with high repetition rates
 

Latest Publications

Below, some topics in the field of process diagnosis of the group Ultrashort Pulse Processing are shown:

  • Investigation of the formation dynamics of ultrathin graphite following excitation of ultrashort pulsed laser radiation
  • Temporal evolution of free electrons while processing glass
  • Pulse-to-pulse interaction during materials processing with high repetition rates