Integrated Optical Memory Based on Laser-Written Waveguides

18 May 2016

Our paper ” Integrated Optical Memory Based on Laser-Written Waveguides” has been published in Physical Review Applied. In this work, we collaborate with Giacomo Corrielli, an alumni of our group, Roberto Osellame from Politecnico di Milano. The work was selected as Editors´ suggestion.

Quantum memory is an essential building block for applications in quantum information science, where scalability and integrability are needed for progress toward large-scale architectures. The authors present a platform for integrated photonic memory, based on laser-written waveguides in rare-earth-doped crystals. The coherence properties of the optically active ions persist after micromachining, enabling proof-of-principle light storage using the full atomic-frequency-comb protocol. This is a pioneering demonstration of on-demand optical memory on a chip.

Figure 1: Illustration of a laser written waveguide

Abstract

We propose and demonstrate a physical platform for the realization of integrated photonic memories based on laser-written waveguides in rare-earth-doped crystals. Using femtosecond-laser micromachining, we fabricate waveguides in Pr3+Y2SiO5 crystal. We demonstrate that the waveguide inscription does not affect the coherence properties of the material and that the light confinement in the waveguide increases the interaction with the active ions by a factor of 6. We also demonstrate that analogous to the bulk crystals, we can operate the optical pumping protocols necessary to prepare the population in atomic-frequency combs that we use to demonstrate light storage in excited and spin states of the Praseodymium ions. Our results represent a realization of laser-written waveguides in a Pr3+Y2SiO5 crystal and an implementation of an integrated on-demand spin-wave optical memory. They open perspectives for integrated quantum memories.

Ref: Integrated Optical Memory Based on Laser-Written Waveguides
Giacomo Corrielli, Alessandro Seri, Margherita Mazzera, Roberto Osellame, and Hugues de Riedmatten
Phys. Rev. Applied 5, 054013 (2016)