Large-area multispectral superconducting nanowire single-photon detector.

Area of Science:

• Optics and Photonics
• Quantum Technologies
• Materials Science

Background:

• Superconducting nanowire single-photon detectors (SNSPDs) are crucial for quantum information science and free-space optical communication.
• Existing SNSPDs often have limited active areas or spectral ranges, hindering their application in complex free-space scenarios.
• There is a need for detectors capable of simultaneously sensing multiple wavelengths with high efficiency and low timing jitter.

Purpose of the Study:

• To report a novel, large-active-area multispectral SNSPD.
• To demonstrate simultaneous single-photon detection at three key wavelengths (532, 850, and 1064 nm).
• To evaluate the detector's performance in terms of system detection efficiency (SDE) and timing jitter for free-space applications.

Main Methods:

• Fabrication of a 35 µm diameter NbTiN nanowire SNSPD integrated with dielectric mirrors.
• Characterization of the detector's spectral response and efficiency using polarized and unpolarized light at 532, 850, and 1064 nm.
• Coupling the detector with both single-mode (SMF-28) and multimode (50 µm) fibers to assess performance under different coupling conditions.

Main Results:

• Maximal SDEs of 80.0% at 532/850 nm and 75.8% at 1064 nm achieved with SMF-28 fiber for polarized light.
• SDEs of 68.6% (532 nm), 59.6% (850 nm), and 47.0% (1064 nm) achieved with multimode fiber for unpolarized light.
• Low timing jitters of 37.1 ps (SMF-28) and 41.0 ps (multimode fiber) were recorded.

Conclusions:

• The developed large-active-area multispectral SNSPD offers high performance across multiple wavelengths.
• The detector's capability for simultaneous multiwavelength detection is highly promising for diverse free-space applications.
• This technology advances the development of robust optical sensing systems for quantum and communication technologies.