Detection of CO2 laser power variations via electric field changes nearby the plasma tube

Measurements of electric field changes near the laser tube can be a source of new information of phenomena in the laser plasma. The authors studied a phenomenon called 'antenna effect' which can be used for laser stabilization. The experimental set-up is presented. A bar of metallic foil wound around the water-jacket of CO2 laser plasma tube was used as a probe ('antenna'). The antenna effect technique provides a convenient method for observing the laser signiture. The antenna effect was used successfully for detectorless stabilization of a laser frequency and in plasma diagnostic set-up. (author)