4 research outputs found
Generation of counterpropagating and spectrally uncorrelated photon-pair states by spontaneous four-wave mixing in photonic crystal waveguides
In this work, we propose and theoretically analyze a new scheme for generation of counterpropagating photon pairs in photonic crystal waveguides through the process of spontaneous four-wave mixing. Using the fundamental properties of periodic Bloch modes in a standard photonic crystal waveguide, we demonstrate how modal phase-matching can be reached between forward-propagating pump modes and counterpropagating signal and idler modes, for generation of degenerate and non-degenerate photon pairs. We then show how this scheme can be used for generation of photon pairs that are nearly uncorrelated in the spectral degree of freedom. Such a source will be highly interesting as a heralded source of single photons, especially as the spectrally separable signal and idler photons are also spatially separated directly at the source. We conduct our investigation based on a design in silicon, yet our design concept is general and can in principle be applied to any nanostructured material platform
A Tunable Transition Metal Dichalcogenide Entangled Photon-Pair Source
Entangled photon-pair sources are at the core of quantum applications like
quantum key distribution, sensing, and imaging. Operation in space-limited and
adverse environments such as in satellite-based and mobile communication
requires robust entanglement sources with minimal size and weight requirements.
Here, we meet this challenge by realizing a cubic micrometer scale entangled
photon-pair source in a 3R-stacked transition metal dichalcogenide crystal. Its
crystal symmetry enables the generation of polarization-entangled Bell states
without additional components and provides tunability by simple control of the
pump polarization. Remarkably, generation rate and state tuning are decoupled,
leading to equal generation efficiency and no loss of entanglement. Combining
transition metal dichalcogenides with monolithic cavities and integrated
photonic circuitry or using quasi-phasematching opens the gate towards
ultrasmall and scalable quantum devices