Superconducting single-photon detectors integrated with diamond nanophotonic circuits

Abstract

Photonic quantum technologies hold promise to repeat the success of integrated nanophotonic circuits in non-classical applications. Using linear optical elements, quantum optical computations can be performed with integrated optical circuits and can therefore overcome the existing limitations in terms of scalability. In addition to passive optical devices for realizing photonic quantum gates, active elements, such as single-photon sources and single-photon detectors, are essential ingredients for future optical quantum circuits. Material systems that allow for the monolithic integration of all components are particularly attractive, including III-V semiconductors, silicon and diamond. Here, we demonstrate nanophotonic integrated circuits made from high-quality polycrystalline diamond thin films in combination with on-chip single-photon detectors. By using superconducting nanowires that are coupled evanescently to traveling waves, we achieve high detection efficiencies of up to 66% as well as low dark count rates and a timing resolution of 190 ps. Our devices are fully scalable and hold promise for functional diamond photonic quantum devices.

Travelling-wave single-photon detectors integrated with diamond photonic circuits: operation at visible and telecom wavelengths with a timing jitter down to 23 ps

“…3b. For NIR photons we obtain minimum NEP of 1.4×10 -18 W/Hz 1/2 at a normalized bias current of 85%, on par with previous results 9,10 , while in the visible wavelength regime the minimum NEP value is reached at a low bias current of 60% and reaches 4.4×10 -19 W/Hz 1/2 . We note that the large error bars towards low bias currents are due to the uncertainty in dark count rates below 1 Hz, due to a data acquisition time of 20 times 2 s per data point in the experiment.…”

“…9,12 This includes the structuring of nanowires into niobium nitride (NbN) thin films using HSQ negative resist, as shown in the scanning electron microscope image Fig. 1b.…”

Optically probing the detection mechanism in a molybdenum silicide superconducting nanowire single-photon detector

“…Their low dark count rate, fast response time, small jitter, and high efficiency favour their use in various demanding quantum optics applications such as quantum key distribution, 3 quantum networking, 4 device-independent quantum information processing 5 and deep-space optical communication. 6 Notably, SNSPDs can be integrated into photonic circuits, 7,8 and their applications extend beyond quantum optics, including light detection and ranging, 9 integrated circuit testing, 10 and fiber optic sensing. 11 One recent important advance in the SNSPD field has been the introduction of amorphous superconductors such as tungsten silicide (WSi), 12 molybdenum silicide (MoSi) 13,14 and molybdenum germanium (MoGe).…”

Diamond as a material for monolithically integrated optical and optomechanical devices

“…Using ion implantation for site-specific single photon source realization [130,131] will eventually allow for devising On-chip detection efficiency of a SNSPD of 100 nm wire width and 65 mm length at varying bias current I bias . Maximum detection efficiency of up to 66% is observed [125]. Inset: layout of the nanowire detector (red) on top of a nanophotonic waveguide (grey).…”