Soft X-ray laser interferometer used for dense plasma diagnostics

Laser interferometry allows the recording of the electron density in a great variety of plasmas. However, the absorption and refraction imposes a limitation to the maximum density, plasma size and plasma gradient that can be measured with this technique, The development of compact soft X-ray laser sources gives the opportunity to extend the limits of plasma interferometry, probing plasmas with high densities and steep gradients. We present results of plasma interferometry using an amplitude division interferometer and a table top soft X-ray laser. The interferometer is a modified Mach-Zehnder configuration with diffraction gratings used as beam splitters. The soft X-ray laser is a 46.9 nm capillary discharge table-top laser. The set up was used to probe a laser-created plasma with a temporal resolution of similar to1 ns and densities up to 6 10(20) cm(-3).