Electrostatic levitation

The sample to be examined is electrically charged and made to float in a vertical static electric field between two electrodes arranged one above the other (voltage: approx. 20 kV). Two orthogonal horizontal fields between two side electrodes (voltage: approx. ± 3 kV) prevent the sample from moving sideways. The 3-dimensional position control of the sample is carried out via two expanded laser beams, which cast the shadow of the sample onto two flat position-sensitive detectors (PSD). The UV radiation from a deuterium arc lamp enables the sample to retain its charge via the photoelectric effect. Two 25 W diode lasers (wavelength: 810 nm) are used to heat the sample material. The temperature is measured using a pyrometer.