Pulsed laser ablation (PLA) in high-density media—high-pressure gases, liquids, and supercritical fluids—has shown to be promising for nanomaterials fabrication and as an analysis technique in extreme environments, for example, the exploration of deep ocean levels and planetary atmospheres and surfaces. Despite the high potential of this technique, it is still not very widely used. The objective of the present chapter is to present the reader with an overview of recent advances in the use of pulsed laser ablation in pressurized media, the fundamental characteristics, especially the dynamics of cavitation bubbles and the optical emission, and the applications to the fabrication of metallic and semiconductor nanoparticles, and diamond molecules, the so-called diamondoids. Finally, a short overview of the use of pulsed laser ablation in pressurized media as a promising tool for the analysis of extreme environments is presented.
Part of the book: Applications of Laser Ablation
Dusty plasmas, which are systems comprising plasmas and dust particles, have emerged in various fields such as astrophysics and semiconductor processes. The fine particles possibly form ordered structures, namely, plasma crystals, which have been extensively studied as a model to observe statistical phenomena. However, the structures of the plasma crystals in ground-based experiments are two-dimensional (2D) because of the anisotropy induced by gravity. Microgravity experiments successfully provided opportunities to observe the novel phenomena hidden by gravity. The dusty plasmas generated in supercritical fluids (SCFs) are proposed herein as a means for realizing a pseudo-microgravity environment for plasma crystals. SCF has a high and controllable density; therefore, the particles in SCF can experience pseudo-microgravity conditions with the aid of buoyancy. In this chapter, a study on the particle charging and the formation of the plasma crystals in supercritical CO2, the realization of a pseudo-microgravity environment, and the outlook for the dusty plasmas in SCF are introduced. Our studies on dusty plasmas in SCF not only provide the pseudo-microgravity conditions but also open a novel field of strongly coupled plasmas because of the properties of media.
Part of the book: Progress in Fine Particle Plasmas