Observation of squeezed states with strong photon number oscillations

TL;DR

This paper reports the observation of highly pure, strong squeezed states of light with a record 11.5 dB squeezing, high bandwidth, and photon number oscillations, advancing quantum measurement and information technologies.

Contribution

It presents the strongest squeezing observed to date with high purity and bandwidth, and reveals photon number oscillations and higher-order photon pairs in the generated states.

Findings

11.5 dB squeezing achieved

Vacuum contribution less than 5%

Squeezing bandwidth of 170 MHz

Abstract

Squeezed states of light constitute an important nonclassical resource in the field of high-precision measurements, e.g. gravitational wave detection, as well as in the field of quantum information, e.g. for teleportation, quantum cryptography, and distribution of entanglement in quantum computation networks. Strong squeezing in combination with high purity, high bandwidth and high spatial mode quality is desirable in order to achieve significantly improved performances contrasting any classical protocols. Here we report on the observation of the strongest squeezing to date of 11.5 dB, together with unprecedented high state purity corresponding to a vacuum contribution of less than 5%, and a squeezing bandwidth of about 170 MHz. The analysis of our squeezed states reveals a significant production of higher-order pairs of quantum-correlated photons, and the existence of strong photon number oscillations.