A 64-pixel NbTiN superconducting nanowire single-photon detector array for spatially resolved photon detection

Area of Science:

• Quantum optics
• Solid-state physics
• Nanotechnology

Background:

• Superconducting nanowire single-photon detectors (SSPDs) are crucial for sensitive light detection.
• Developing large-format SSPD arrays is essential for advanced imaging and sensing applications.
• Uniformity and high yield in SSPD fabrication remain key challenges.

Purpose of the Study:

• To characterize a two-dimensionally arranged 64-pixel niobium-titanium-nitride (NbTiN) SSPD array.
• To evaluate the array's capability for spatially resolved photon detection.
• To assess the uniformity and single-photon sensitivity of the SSPD pixels.

Main Methods:

• Fabrication of NbTiN SSPD pixels on thermally oxidized silicon substrates.
• Characterization of superconducting properties (transition temperature, switching current) for all 64 pixels.
• Measurement of single-photon sensitivity and pulse generation probability.
• Spatial mapping of photon flux intensity using an optical fiber and analysis of system detection efficiency (SDE) variations.

Main Results:

• High-yield production of uniform, high-quality SSPD pixels.
• Consistent superconducting characteristics across all 64 pixels (Tc: 7.19-7.23 K, Ic: 15.8-17.8 μA).
• All pixels exhibited single-photon sensitivity, with 93.75% (60/64) showing >90% pulse generation probability.
• Spatial photon detection demonstrated a Gaussian distribution of SDE, correlating with photon flux intensity.

Conclusions:

• The 64-pixel NbTiN SSPD array is successfully fabricated and characterized.
• The array exhibits excellent uniformity and high single-photon detection efficiency.
• This technology is suitable for spatially resolved photon detection and advanced optical sensing.