How Does a Ceramic Melt Under Laser? Tunnel Ionization Dominant Femtosecond Ultrafast Melting in Magnesium Oxide

TY - JOUR

T1 - How Does a Ceramic Melt Under Laser? Tunnel Ionization Dominant Femtosecond Ultrafast Melting in Magnesium Oxide

AU - Zhao, Hui

AU - Hu, Shiqi

AU - Guan, Mengxue

AU - Liu, Xinbao

AU - Chen, Daqiang

AU - Xu, Jiyu

AU - Meng, Sheng

N1 - Publisher Copyright: Copyright © 2025 Hui Zhao et al.

PY - 2025

Y1 - 2025

N2 - Laser-induced melting plays a crucial role in advanced manufacturing technology and ultrafast science; however, its atomic processes and microscopic mechanisms, especially in a wide-gap ceramic, remain elusive due to complex interplays between many degrees of freedom within a timescale of ~100 fs. We report here that laser melting is greatly accelerated by intense laser-induced tunnel ionization, instead of a priori multiphoton absorption, in the archetypal ceramic magnesium oxide (MgO). The tunneling processes generate a large number of photocarriers and results in intense energy absorption, instantaneously altering the potential energy surface of lattice configuration. The strong electron–phonon couplings and fast carrier relaxation enable efficient energy transfer between electrons and the lattice. These results account well for the latest ultrafast melting experiments and provide atomistic details and nonequilibrium mechanism of photoinduced ultrafast phase transitions in wide-gap materials. The laser modulation of melting thresholds and phase boundary demonstrate the possibility of manipulating phase transition on demand. A shock wave curve is also obtained at moderate conditions (P = 2 GPa), extending Hugoniot curve to new regimes.

AB - Laser-induced melting plays a crucial role in advanced manufacturing technology and ultrafast science; however, its atomic processes and microscopic mechanisms, especially in a wide-gap ceramic, remain elusive due to complex interplays between many degrees of freedom within a timescale of ~100 fs. We report here that laser melting is greatly accelerated by intense laser-induced tunnel ionization, instead of a priori multiphoton absorption, in the archetypal ceramic magnesium oxide (MgO). The tunneling processes generate a large number of photocarriers and results in intense energy absorption, instantaneously altering the potential energy surface of lattice configuration. The strong electron–phonon couplings and fast carrier relaxation enable efficient energy transfer between electrons and the lattice. These results account well for the latest ultrafast melting experiments and provide atomistic details and nonequilibrium mechanism of photoinduced ultrafast phase transitions in wide-gap materials. The laser modulation of melting thresholds and phase boundary demonstrate the possibility of manipulating phase transition on demand. A shock wave curve is also obtained at moderate conditions (P = 2 GPa), extending Hugoniot curve to new regimes.

UR - https://www.scopus.com/pages/publications/85219578153

U2 - 10.34133/ultrafastscience.0085

DO - 10.34133/ultrafastscience.0085

M3 - Article

AN - SCOPUS:85219578153

SN - 2765-8791

VL - 5

JO - Ultrafast Science

JF - Ultrafast Science

M1 - 0085

ER -