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This paper includes a brief overview of the contributions and results of several groups working in plasma focus (PF) devices around the world in the last few years. In section 2 a summary of the most important results of the dense transient plasma research programme of the Comisión Chilena de Energía Nuclear is presented. An approach to an integrated vision of the present PF research status is presented in the next section. Some parameters that remain practically constant in PF devices that operate in a wide range of energies from 1?MJ to tens of joules are discussed. These parameters ('plasma energy density parameter' and 'drive parameter') are used as a design tool to achieve an ultra-miniature pinch focus device operating at energies less than 1?J. Preliminary results of such an ultra-miniature device are presented. Applications to non-destructive tests, detection of substances, pulsed radiation in biology and material sciences are also briefly discussed in this paper.

A multiframe technique that uses Fresnel holography is described. Splitting of the initial pulse by means of 50/50 beam splitters provides two sets of eight consecutive pulses with approximately the same energy but with different angles. Each interferogram is recorded separately. The technique has been used to obtain time-resolved Fresnel holographic interferograms of transient electrical discharges, such as Z pinch. A frequency-doubled, Q-switched Nd:YAG laser (6-ns FWHM) is used. A delay between consecutive pulses of 10 ns is achieved, and it is mainly limited by the physical size of the laboratory. Interferograms obtained on a gas-embedded Z pinch are shown.