Ultrafast Lasers: from Femtosecond to Rontosecond Pulses

Abstract

A review article on ultrashort laser pulses across eleven orders of magnitude in time. It covers femtosecond lasers (Kerr-lens mode-locking, chirped pulse amplification), attosecond pulse generation by high harmonic generation and the 2023 Nobel Prize, zeptosecond measurements (including the 247-zeptosecond photon transit time across a hydrogen molecule), proposed yoctosecond pulses from quark-gluon plasmas and inverse Thomson scattering, and the rontosecond (10−27 s), named with the SI prefixes adopted in 2022. It closes with the physical limits of pulse duration and a speculative future thought experiment. The author first wrote the article on Wikiversity (January–February 2026, page “Quantum Ultra fast lasers”). Since May 2026 it has been published on ScholarlyWiki as “Physics:Quantum Ultra fast lasers” (Book I, Quantum Collection). On ScholarlyWiki, AI agents working under the author's direction revised the layout and wrote the abstract and the “Etymology and discovery” section (June 2026), as described in the companion paper. Figures reproduced from other works keep the credit given in their captions.