Design of modular multi-channel electron spectrometers for application in laser matter interaction experiments at Prague Asterix Laser System.

This paper describes design, development, and implementation of a multi-channel magnetic electron spectrometer for the application in laser-plasma interaction experiments carried out at the Prague Asterix Laser System. Modular design of the spectrometer allows the setup in variable configurations to evaluate the angular distribution of hot electron emission. The angular array configuration of the electron spectrometers consists of 16 channels mounted around the target.

Interferometric analysis of sub-nanosecond laser-induced optical breakdown dynamics in the bulk of fused-silica glass.

Dynamics of laser-induced optical breakdown in the bulk of fused-silica glass irradiated by a sub-nanosecond laser pulse at a wavelength of 790 nm with a fluence of 522 J/cm was studied by the femtosecond time-resolved complex interferometry in Nomarski arrangement utilising a Fresnel bi-prism. Evolution of the plasma channel and the development of the free electron density were in focus of the investigation. The measured ultimate length of the plasma channel was equal to 30 μm and almost doubled the length estimated within the moving breakdown model.

Extreme ultraviolet interferometry of warm dense matter in laser plasmas.

We demonstrate that interferometric probing with extreme ultraviolet (EUV) laser light enables determination of the degree of ionization of the "warm dense matter" produced between the critical and ablation surfaces of laser plasmas. Interferometry has been utilized to measure both transmission and phase information for an EUV laser beam at the photon energy of 58.5 eV, probing longitudinally through laser-irradiated plastic (parylene-N) targets (thickness 350 nm) irradiated by a 300 ps duration pulse of wavelength 438 nm and peak irradiance 10(12) W cm(-2).

Abel inversion using fast Fourier transforms.

A fast Fourier transform based Abel inversion technique is proposed. The method is faster than previously used techniques, potentially very accurate (even for a relatively small number of points), and capable of handling large data sets. The technique is discussed in the context of its use with 2-D digital interferogram analysis algorithms.

Phase-amplitude imaging: its application to fully automated analysis of magnetic field measurements in laser-produced plasmas.

An interferometric technique which enables simultaneous phase and amplitude imaging of optically transparent objects is discussed with respect to its application for the measurement of spontaneous toroidal magnetic fields generated in laser-produced plasmas. It is shown that this technique can replace the normal independent pair of optical systems (interferometry and shadowgraphy) by one system and use computer image processing to recover both the plasma density and magnetic field information with high accuracy. A fully automatic algorithm for the numerical analysis of the data has been developed and its performance demonstrated for the case of simulated as well as experimental data.