Photodetection and Induced Squeezing

M. Sebawe Abdalla, Saad S. M. Hassan

Hiroki Saito, Masahito Ueda

Spin squeezing of an ensemble of N atoms in a high-Q cavity is enhanced by continuous measurement of photons in the cavity. A degree of spin squeezing proportional to ${N}^{\ensuremath{-}1/3}$ is achieved as a quasi-steady-state over a broad set of initial states of atoms and photons. Our method of spin squeezing is robust against the imperfect photodetection efficiency in current experiments.

Michel De Haan

Tetsuo Ogawa, Masahito Ueda, Nobuyuki Imoto

A general quantum theory of continuous photodetection is applied to an initially squeezed state to clarify effects of quantum-mechanical measurement backaction on a highly nonclassical field. The remaining photon field is found to oscillate in time between super- and sub-Poissonian photon statistics due to the backaction of the photon-number measurement.

Jasper Kranias

A jupyter notebook used to generate figures for the paper "Photodetection of Squeezed Light: a Whittaker-Shannon Analysis" by Kranias et. al. The software can also be found at https://github.com/JKranias/Whittaker-Shannon-Decomposition.

Haoran Chen, Benjamin Westcott, Fatemehsadat Tabatabaei +10 more

Squeezed light underpins quantum-enhanced sensing and continuous-variable quantum information processing, and integrated photonics offers a route to producing it at scale. Universal to these applications are squeezed-light generation and measurement. Importantly, quantum measurements serve not only as readout but also as active operations in quantum-state evolution. However, integrating squeezed-light generation and photodetection on the same photonic chip has remained challenging because they impose fundamentally conflicting material requirements: low optical loss to preserve quantum correlations, but efficient photon absorption for photodetection. Here, we demonstrate squeezed-light generation, routing, and balanced homodyne detection integrated on a single photonic chip through heterogeneous integration. A two-mode squeezed quantum microcomb comprising 34 quantum modes is measured with approximately 3 dB squeezing. Our work establishes a scalable architecture for fully integrated squeezed-light quantum photonic systems, unifying quantum-state generation, processing, and detection on a single chip.