Background-Free Near-Infrared Biphoton Emission from Single GaAs Nanowires

Abstract

The generation of photon pairs from nanoscale structures with high rates is still a challenge for the integration of quantum devices, as it suffers from parasitic signals from the substrate. In this work, we report type-0 spontaneous parametric down-conversion at 1550 nm from individual bottom-up grown zinc-blende GaAs nanowires with lengths of up to 5 μm and diameters of up to 450 nm. The nanowires were deposited on a transparent ITO substrate, and we measured a background-free coincidence rate of 0.05 Hz in a Hanbury–Brown–Twiss setup. Taking into account transmission losses, the pump fluence, and the nanowire volume, we achieved a biphoton generation of 60 GHz/Wm, which is at least 3 times higher than that of previously reported single nonlinear micro- and nanostructures. We also studied the correlations between the second-harmonic generation and the spontaneous parametric down-conversion intensities with respect to the pump polarization and in different individual nanowires.

Nonlinear nanoresonators for Bell state generation

“…Recently, there have been several experimental demonstrations of photon-pair generation 12 and manipulation 13,14 in much smaller nonlinear systems, with at least one subwavelength-sized dimension, like thin films, [15][16][17][18] nanowires, 19 dielectric nanoresonators, 20 and metasurfaces. [21][22][23][24] For instance, Ref.…”

Temporally Distilled High-Dimensional Biphotonic States from Thin Sources

“…In linear and nonlinear optics, flat optical devices already outperform their bulk counterparts, especially in terms of tunability and multifunctionality. , “Flat” platforms are also promising sources of quantum light, including single-photon and two-photon states. − Miniaturized two-photon sources mainly use spontaneous parametric down-conversion (SPDC) without momentum conservation, which gives unprecedented flexibility for the engineering of quantum entanglement in position-momentum, , time-frequency, and polarization, although at the cost of low-generation efficiency. Researchers try out different materials and designs for nanoscale sources of quantum light, investigating new approaches for generation rate enhancement, quantum state engineering, and adding multifunctionality. − …”