This report discusses the optimisation of laser materials processing of polymers and compound materials by employment
of smart sensors which measure laser parameters as well as processing progress online and deliver signals which are used
for instantaneous laser and motion control. The mutual interdependence between suitable laser parameters and given
mechanical, thermal and optical material properties is considered. Some examples of laser cutting, laser milling of
channels and holes with precisely defined depth as well as laser of welding are treated. Process simulation plays an
important part in finding the right adjustment of laser parameters as function of sample properties and processing aim.
Often laser parameters and sample changes have to be measured and controlled very fast between adjacent irradiations of
the sample by pulse sequences (up to about 100 KHz) or between repetition cycles of scanned cw lasers. The same
sensors measure and store the processing results and decide whether the sample finally fulfils all quality criteria. The
value of such laser processing units strongly depends on the smartness of the applied sensors and their interplay with the
laser as a tool.
Mirrorless lasers composed of gain medium and scattering mesoscopic particles are dealt with, where the feedback arising from the arrangement of scatterers determines the parameters of emitted radiation, coherence included. Micro lasers consisting of two particles as well as complex highly ordered and random arrangements of particles have been investigated.
Infrared sensors can profitably be employed in environmental monitoring because of sensitivity, specifity and stability of the interaction between infrared radiation and molecules. Recent progress in infrared sources, spectral filters and detectors allows the construction of small, energy-saving, reliable and almost maintenance-free devices. Almost monolithic integrated optical devices in development.
In general the spatial and temporal profiles of ultrashort light pulses suffer considerable distortions upon propagating through optical devices. This may lead to serious limitations of the spatial and temporal resolution. The distortions can be reduced by using input pulses with appropriate prechirp and optical devices corrected for chromatic and spatial aberrations at the center frequency of the light pulses. The spatial (temporal) resolution can be enhanced by selecting narrow temporal (spatial) parts of the light pulses in the detection process.
Wavelength shifts in optical signals as high as some nanometers originating from signal purTp interaction in semiconductors and organic polymers can be applied for optical swit ching impressing infornation onto signals and pulse compression. 1.