Bursts of polarised single photons from atom-cavity sources
Journal of Physics B: Atomic, Molecular and Optical Physics IOP Publishing 56:20 (2023) 205003
Abstract:
Photonic qubits play an instrumental role in the development of advanced quantum technologies, including quantum networking, boson sampling and measurement based quantum computing. A promising framework for the deterministic production of indistinguishable single photons is an atomic emitter coupled to a single mode of a high finesse optical cavity. Polarisation control is an important cornerstone, particularly when the polarisation defines the state of a quantum bit. Here, we propose a scheme for producing bursts of polarised single photons by coupling a generalised atomic emitter to an optical cavity, exploiting a particular choice of quantisation axis. In connection with two re-preparation methods, simulations predict ten-photon bursts coincidence count rates on the order of 1 kHz with single $^{87}\mathrm{Rb}$ atoms trapped in a state of the art optical cavity. This paves the way for novel n-photon experiments with atom-cavity sources.Multi-resonant open-access microcavity arrays for light matter interaction
Optics Express Optica Publishing Group 31:4 (2023) 6342-6355
Abstract:
We report the realisation of a high-finesse open-access cavity array, tailored towards the creation of multiple coherent light-matter interfaces within a compact environment. We describe the key technical developments put in place to fabricate such a system, comprising the creation of tapered pyramidal substrates and an in-house laser machining setup. Cavities made from these mirrors are characterised, by laser spectroscopy, to possess similar optical properties to state-of-the-art fibre-tip cavities, but offer a compelling route towards improved performance, even when used to support only a single mode. The implementation of a 2×2 cavity array and the independent frequency tuning between three neighbouring sites are demonstrated.[Data] Multi-resonant open-access microcavity arrays for light matter interaction
University of Oxford (2023)
Abstract:
Data presented and analysed in arXiv:2207.03676 [physics.optics] [https://arxiv.org/abs/2207.03676].How to administer an antidote to Schrödinger's cat
Journal of Physics B: Atomic, Molecular and Optical Physics 55:5 (2022)
Abstract:
In his 1935 Gedankenexperiment, Erwin Schrödinger imagined a box with a cat and a poisonous substance which has a 50% probability of being released, based on the decay of a radioactive atom. As such, the life of the cat and the state of the poison become entangled, and the fate of the cat is determined upon opening the box. We present an experimental technique that keeps the cat alive on any account. This method relies on the time-resolved Hong-Ou-Mandel effect: two long, identical photons impinging on a beam splitter always bunch in either of the outputs. Interpreting the first photon detection as the state of the poison, the second photon is identified as the state of the cat. Even after the collapse of the first photon's state, we show their fates are intertwined through quantum interference. We demonstrate this by a sudden phase change between the inputs, administered conditionally on the outcome of the first detection, which steers the second photon to a pre-defined output and ensures that the cat is always observed alive.Polarized single photons from a cavity-enhanced atom-light interface with coherent re-preparation
Optica Publishing Group (2022) qth4c.4