Synthesis of high-pressure phases of silica by laser-induced optical breakdown

We report on synthesis of compressed silica phase formed inside a α -quartz host crystal using powerful shock-wave and thermal transients generated via local optical breakdown induced by low-energy, tightly focused femtosecond laser pulses. Structural characterization of irradiated areas by the X-ray diffraction technique reveals signatures of a new high-pressure phase of silica, which is theoretically expected to form at a pressure of 120 GPa.