Laser-induced chemical micro-treatment and synthesis of materials

Laser-induced technological chemical processes can significantly contribute to the development of new methods for micro treatment of materials and hence to the broadening of the application spectrum of laser microtechnology. In this paper three typical laser-activated chemical technological methods in liquids, gases and solids and their possible applications are presented and discussed: First, laser-induced liquid-phase jet-chemical etching of metals. In this method, laser radiation which is guided from a coaxially expanding liquid jet-stream initiates locally on a metal surface a thermochemical etching reaction, which leads to a selective material removal at high resolution (< 1μm) and quality of the treated surface. Second, local photon-plasma induced synthesis of thin film coatings. This technological method is based on thermochemical CVD processes taking place in a photon-initiated stationary plasma maintained in the electromagnetic optical field of a high-power cw-CO2 laser radiation. This method allows synthesis of thin-film coatings in the open-air atmosphere without using vacuum or reaction chamber. Third, laser-induced photochemical modification of the optical properties of polymers. This method is based on the local controllable change of the polymer structure leading to modification of the refractive index in the treated area. By numerous independently adjustable laser radiation parameters, for instance wavelength and irradiation dose, the modification process can be controllably driven in order to generate desired functional properties.