Single-Shot Pulse Retrieval of Femtosecond Bright Squeezed Vacuum

Bright squeezed vacuum (BSV) takes the phenomenon of squeezed vacuum to the extreme [1]. Extremely high photon numbers of up to 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">13</sup> can be found inside a single BSV pulse due to the antisqueezed quadrature, with effective pulse durations down to tens of femtoseconds [2]. BSV is sufficiently intense to drive nonperturbative HHG from solids [2] and multiphoton electron emission from nanotips [3]. Intriguingly, BSV has the potential to explore sub-cycle light-matter interactions above the conventional damage threshold [2]. However, characterizing the full temporal properties (mean and distribution) of BSV pulses has remained elusive. Here we overcome this challenge by full temporal characterization (amplitude and phase) of single-shot BSV pulses, for the first time.