Physics

A milestone in petahertz electronics

In a semiconductor, electrons can be excited by absorbing laser light. Advances in the past decade have enabled measuring this fundamental physical mechanism on timescales below a femtosecond (10-15 s). Now, physicists at ETH Zurich have resolved the response of electrons in gallium arsenide at the attosecond (10-18 s) timescale, and gained unexpected insights for future ultrafast opto-electronic devices with operation frequencies in the petahertz regime.