Deterministic source of photon number states.

Entangled multi-particle states can be utilized for precision measurements, providing tools to reach the so-called Heisenberg limit and thereby overcome the shot-noise limit (the fundamental noise limit for classical systems), enabling measurements with precision unattainable by classical sensors. Quantum photon-number states, also known as Fock states, are the key ingredient to realizing the most useful entangled multi-particle states, such as Holland-Burnett states, cat states, tensor network states, and other multiple-photon entangled states. Furthermore, photon-number states have applications in quantum communication and quantum information sciences.

Physical Sciences Inc. and the University of Illinois Urbana-Champaign are developing a pseudo-deterministic source of photon-number states. The source is based on spontaneous parametric down-conversion (SPDC) inside a low-loss optical loop and will produce quantum photon-number states on demand at a telecommunications wavelength, with an order-of-magnitude higher rate than would otherwise be achievable.

 In this presentation, we will discuss progress towards quantum photon-number states, including the development of the SPDC source, construction and testing of a low-loss optical storage loop, and a numerical model predicting the overall performance of the source for realistic experimental parameters.