Plasma dynamics and structural modifications induced by femtosecond laser pulses in quartz

► Irradiation of quartz with single fs laser pulses at increasing pulse energies. ► Ablation at high local fluences and surface depression at low fluences. ► Fs-microscopy shows that free electron plasma causes surface depression. ► Surface depression is consistent with an increased material density. ► Low steady-sate reflectivity indicates creation of defects.