| Popis: |
In this chapter, we present the state-of-the-art knowledge on the microscopic mechanisms of direct laser writing by multiphoton polymerization as well as the underlying experiments. Due to the small reaction volume and the high exposure intensity, the reaction conditions are very specific in this case compared with other applications in the broader fields of laser materials processing and photopolymerization. We will therefore focus on experiments that show how the common photophysical and photochemical reaction models from these other fields must be adapted. These include the experimental discrimination of the excitation mechanism through variation of the laser repetition rate, the measurement of the local heating during the writing process, the detection of the monomer conversion through Raman spectroscopy techniques, the investigation of the influence of oxygen quenching and oxygen diffusion, and the experimental determination of the duration of the polymerization reaction. |
