Processing of micro-particles by UV laser irradiation in a field cage

An electric cage-laser micro-turning lathe was realised and applied to cont act-free handling and mechanical processing of micro particles. Since parti cles with diameters of several micrometers cannot be fixed in mechanical ch ucks, an octode field cage was used to trap and rotate a single particle in a fluid without any mechanical surface contact. A pulsed nitrogen laser of high beam quality focused to about 1 mu m in diameter could be adjusted in dependently of the cage position, The trapping forces (negative dielectroph oresis) acting on a bead of 5 to 15 mu m are up to several hundred pN. This and the surrounding fluid damp down the effect of the laser pulses during bead processing. Examples demonstrating the possibilities of this technique are shown. Microsystems with high optical quality were fabricated photolit hographically or by laser direct-write chemical vapor deposition (LCVD). Te chnical and biotechnological applications are discussed.