Southwest Quantum Information and Technology

Sub-cycle quantum optics: Direct sampling of vacuum fluctuations in experiment and theory

Presenting Author: Denis Seletskiy, (Konstanz)
Contributing Author(s): Claudius Riek, Andrey S. Moskalenko, Guido Burkard, Alfred Leitenstorfer

Study and manipulation of the ground state of the radiation field is one of the central subjects in quantum optics. In a typical approach of homodyne detection, the information is averaged over multiple cycles of light and amplification to finite intensity is necessary. We demonstrate direct detection of the vacuum fluctuations of the local electric field amplitude in free space via the linear Pockels effect. Broadband electro-optic sampling with gate pulses shorter than 6 femtoseconds enables quantum-statistic readout [1]. Distinction from the detector shot noise is achieved by modification of the sampled space-time volume, defined by an effective temporal duration and the spatial extent of the pulse in the electro-optic medium [1,2]. Ensuring an optimal detection bandwidth which matches the center frequency, here 70 THz, maximizes the vacuum amplitude since the ground-state energy approaches half a photon per optical cycle. The determined magnitude of the vacuum field [1] is in excellent agreement with paraxial theory [2]. Sub-cycle resolution of the oscillating noise in the field quadrature with substantial excursions below the bare vacuum level is predicted [2] and currently explored in the laboratory. Our collective findings open up a new avenue to quantum analysis and manipulation of light in the extreme time-domain limit ensuring sub-cycle access to the electric-field quadrature. [1] C. Riek et al, Science 350, 420 (2015). [2] A. S. Moskalenko et al., arXiv:1508.06953, accepted in PRL

Read this article online: http://www.sciencemag.org/content/350/6259/420.abstract, http://arxiv.org/abs/1508.06953

(Session 9a : Friday from 5:00 pm - 5:30 pm)