Quantum nanophotonics is inevitable

Christophe Couteau

Mahmoud Almassri, Mohammed F. Saleh

In this paper, we propose exploiting dispersion-engineered nanophotonic waveguides in generating unprecedented ultra-broadband spectral and polarisation entanglement using spontaneous four-wave mixing parametric processes. We developed a simplified theoretical quantum framework to investigate and analyze these interactions under pulse source excitations. Using aluminum gallium arsenide and thin-film lithium niobate waveguides, we anticipate obtaining photon pairs with high-dimensional frequency entanglement, characterized by Schmidt numbers as large as 10 8 , and covering the wavelength range 940–2730 nm (equivalent to a 210 THz bandwidth). Additionally, we show that Al 0.3 Ga 0.7 As waveguides with hybrid cladding can enable the generation of polarisation-entangled photon pairs with concurrence exceeding 0.93 across wavelengths from 1175 nm to 1750 nm, spanning almost across all the telecommunication bands with only approximately 27 nm window inevitable-degradation around the pump wavelength. We envisage that these introduced integrated on-chip sources will significantly advance quantum photonic technologies, enabling breakthroughs in multi-channel quantum networking and scalable quantum information systems.

David F. P. Pile

Yiming Lai, Daniel D. A. Clarke, Philipp Grimm +8 more

Light-matter superposition states obtained via strong coupling play a decisive role in quantum information processing, but the deleterious effects of material dissipation and environment-induced decoherence inevitably destroy coherent light-matter polaritons over time. Here, we propose the use of coherent perfect absorption under near-field driving to prepare and protect the polaritonic states of a single quantum emitter interacting with a plasmonic nanocavity at room temperature. Our scheme of quantum nanoplasmonic coherent perfect absorption leverages an inherent frequency specificity to selectively initialize the coupled system in a chosen plasmon-emitter dressed state, while the coherent, unidirectional and non-perturbing near-field energy transfer from a proximal plasmonic waveguide can in principle render the dressed state robust against dynamic dissipation under ambient conditions. Our study establishes a previously unexplored paradigm for quantum state preparation and coherence preservation in plasmonic cavity quantum electrodynamics, offering compelling prospects for elevating quantum nanophotonic technologies to ambient temperatures.

Shuo Sun

I will discuss applications of nanophotonics in quantum optics and solid-state quantum information. I will show how we construct a coherent spin-photon interface in a semiconductor chip by employing nanophotonic cavities, and outline new opportunities by employing novel and integrated nanophotonic structures.

Tristan Bernhard Horst Tentrup, Lyubov V. Amitonova, Klaas‐Jan Gorter +13 more