Time-resolved shadowgraphs of transient plasma induced by spatiotemporally focused femtosecond laser pulses in fused silica glass

TL;DR

This study uses pump-probe shadow imaging to observe the formation and evolution of transient plasma in fused silica glass induced by spatiotemporally focused femtosecond laser pulses, revealing unexpected plasma track curvature due to asymmetric density distribution.

Contribution

First experimental observation of curved plasma tracks in fused silica caused by spatiotemporal focusing effects in femtosecond laser pulses.

Findings

Plasma tracks are significantly curved.

Curvature is due to asymmetric plasma density.

Pulse front tilt influences plasma formation.

Abstract

We report on experimental observations of formation and evolution of transient plasma produced in fused silica glass with spatiotemporally focused (STF) femtosecond laser pulses using a pump-probe shadow imaging technique. Surprisingly, the observation shows that the track of the plasma is significantly curved, which is attributed to an asymmetric density distribution of the transient plasma produced in the focal volume caused by the pulse front tilt of the STF laser field.