<title>Application of fast three-frame interferometry to investigation of laser plasma</title>

The new design of three-frame interferometer is proposed. The optical system of the interferometer, though very simple, has some advantages in comparison with classical interferometers (e.g., Mach-Zehnder interferometer). For registration and analysis of interferograms the CCD cameras and multichannel image acquisition system are used. The interferometer has been tested in a laser-matter experiment. Some results of plasma investigation are presented.