Bright squeezed vacuum (BSV) is a macroscopic quantum state of light where the mean electric field is zero but the field fluctuations are extremely large and oscillate at twice the harmonic frequency. BSV is intense and can drive ultrafast nonlinear processes, such as high-harmonic generation and photoemission from nanotips. However, BSV pulses have not been characterized before with single-shot resolution. In our work, we built a BSV source at 1040nm wavelength and measured each BSV pulse using spectral interferometry. We found an average pulse duration of 27fs and also demonstrated the pi-phase ambiguity of squeezed vacuum. With this new capability, BSV is suitable for femtosecond and attosecond studies of strong-field physics.

Our work, led by PhD student Yuval Kern and in collaboration with colleagues from the Technion and from the Max Planck Institute for the Science of Light, was published in Optica and made the cover image! Read our paper here and a press release here.