Abstract
Experimental determination in a time‐resolved manner of the number densities of free electrons and neutral atoms in a carbon plasma is obtained with two‐wavelength interferometry. The plasma is produced by a Q‐switched ruby laser with a peak power of 100 MW, and a 3‐W argon‐ion laser is used as the interferometer light source. A maximum free electron density of 1.6 × 1019 cm−3 and a maximum neutral density of 1.6 × 1020 cm−3 are observed.