Apart from investigation the emission properties of plasmas more direct information can often be obtained by laser diagnostics. This is a so-called active diagnostics as the laser light interacts with the plasma. Laser diagnostics are more demanding to set up but the interpretation of the experimental data is most often significantly easier than for passive optical emission spectroscopy.
The lab of EPG is equipped with an FTIR, several pulsed Nd YAG laser and dye lasers, ICCD and photo counting detectors which allow high resolution time and spatial resolved measurements of most of the plasma properties.
The different laser diagnostics at EPG are listed below
Thomson, Rayleigh and Raman scattering
If a laser beam is passing through a plasma, the laser photons can be scattered on free electrons in the plasma (Thomson...Read more
Another active diagnostic technique is Laser Absorption. With this technique, not the scattered photons are detected, but the...Read more
Instead of determining the density of a certain atomic level in the plasma directly from the absorption coefficient, one can also...Read more
If there are negative ions in a plasma, they can be detected by photodetachtment. Photodetachment is the process in which an...Read more
Rydberg atoms are atoms of which the outermost electrons are excited to levels close to the ionization level. The radius of the...Read more
Microwave Cavity Resonance Spectroscopy
MCRS uses a cookie-box shaped microwave cavity which encloses the plasma under investigation. This cavity contains two antennas....Read more