Indistinguishable MHz-narrow heralded photon pairs from a whispering gallery resonator

Bibliographic Details
Title: Indistinguishable MHz-narrow heralded photon pairs from a whispering gallery resonator
Authors: Huang, Sheng-Hsuan, Dirmeier, Thomas, Shafiee, Golnoush, Laiho, Kaisa, Strekalov, Dmitry V., Aiello, Andrea, Leuchs, Gerd, Marquardt, Christoph
Publication Year: 2024
Collection: Physics (Other)
Quantum Physics
Subject Terms: Quantum Physics, Physics - Optics
More Details: Hong-Ou-Mandel interference plays a vital role in many quantum optical applications where indistinguishability of two photons is important. Such photon pairs are commonly generated as the signal and idler in the frequency and polarization-degenerate spontaneous parametric down conversion~(SPDC). To scale this approach to a larger number of photons we demonstrate how two independent signal photons radiated into different spatial modes can be rendered conditionally indistinguishable by a heralding measurement performed on their respective idlers. We use the SPDC in a whispering gallery resonator, which is already proven to be versatile sources of quantum states. Its extreme conversion efficiency allowed us to perform our measurements with only \qty{50}{nW} of in-coupled pump power in each propagation direction. The Hong-Ou-Mandel interference of two counter-propagating signal photons manifested itself in the four-fold coincidence rate, where the two idler photons detection heralds a pair of signal photons with a desired temporal overlap. We achieved the Hong-Ou-Mandel dip contrast of \(74\pm 5\%\). Importantly, the optical bandwidth of all involved photons is of the order of a MHz and is continuously tunable. This, on the one hand, makes it possible to achieve the necessary temporal measurements resolution with standard electronics, and on the other hand, creates a quantum states source compatible with other candidates for qubit implementation, such as optical transitions in solid-state or vaporous systems. We also discuss the possibility of generating photon pairs with similar temporal modes from two different whispering gallery resonators.
Document Type: Working Paper
Access URL: http://arxiv.org/abs/2412.15760
Accession Number: edsarx.2412.15760
Database: arXiv
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