All-optical single-shot complete electric field measurement of extreme ultraviolet free electron laser pulses

Recent advances in ultrafast extreme ultraviolet (EUV) and x-ray light sources provide direct access to fundamental time and length scales for biology, chemistry, and materials physics. However, such light pulses are challenging to measure due to the need for femtosecond time resolution at difficult-to-detect wavelengths. Also, single-shot measurements are needed because severe pulse-to-pulse fluctuations are common. Here we demonstrate single-shot, complete field measurements by applying a novel version of frequency resolved optical gating. An EUV free electron laser beam creates a transient grating containing the pulse's electric field information, which is read out with a 400 nm probe pulse. By varying the time delay between two copies of the EUV pump, rather than between the pump and the probe, we separate the needed coherent wave mixing from the slow incoherent response. Because this approach uses photoionization, it should be applicable from the vacuum ultraviolet to hard x rays. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing AgreementY

Automated summary

Recent advances in ultrafast extreme ultraviolet (EUV) and x-ray light sources have provided direct access to fundamental time and length scales for biology, chemistry, and materials physics. However, measuring such light pulses is challenging due to the need for femtosecond time resolution at difficult-to-detect wavelengths. By utilizing a novel version of frequency resolved optical gating, single-shot, complete field measurements have been demonstrated, offering new possibilities for research in various fields.