Laser-Induced Microexplosion Confined in the Bulk of a Sapphire Crystal: Evidence of Multimegabar Pressures

TLDR

A 100‑nJ, 800‑nm, 200‑fs laser pulse focused inside sapphire generates >10^14 W/cm² intensity, ionizing ~0.2 µm³ of material into plasma within femtoseconds. The experiment produced ~10 TPa pressures and 5×10^5 K temperatures, generating strong shock and rarefaction waves that formed a nanovoid surrounded by a shock‑affected shell, with the results explainable by plasma hydrodynamics and enabling study of matter under record heating and cooling rates of 10^18 K/s.

Abstract

Extremely high pressures (approximately 10 TPa) and temperatures (5 x 10(5) K) have been produced using a single laser pulse (100 nJ, 800 nm, 200 fs) focused inside a sapphire crystal. The laser pulse creates an intensity over 10(14) W/cm2 converting material within the absorbing volume of approximately 0.2 microm3 into plasma in a few fs. A pressure of approximately 10 TPa, far exceeding the strength of any material, is created generating strong shock and rarefaction waves. This results in the formation of a nanovoid surrounded by a shell of shock-affected material inside undamaged crystal. Analysis of the size of the void and the shock-affected zone versus the deposited energy shows that the experimental results can be understood on the basis of conservation laws and be modeled by plasma hydrodynamics. Matter subjected to record heating and cooling rates of 10(18) K/s can, thus, be studied in a well-controlled laboratory environment.