Single photon detection at T = 20 K using a two-dimensional cuprate superconductor

Superconducting single-photon detectors constitute a key enabling technology for quantum photonics, both in free-space and on-chip architectures.

Still, the low critical temperature (T_c < 5 K) of commercial superconducting thin films precludes their application in a wider range of fields. High-temperature superconductors, such as the cuprates, offer the prospect of detecting single photons at moderate cryogenic temperatures [1].

Here, we report single-photon detection in few-layer flakes of the 2D cuprate superconductor Bi₂Sr₂CaCu₂O_8+δ at a record temperature of 20 K for telecom wavelengths (λ = 1550 nm).

We combine van der Waals fabrication techniques with novel non-destructive nanopatterning to define 2D cuprate nanowires.

These high-temperature superconducting nanowires exhibit sharp current-voltage characteristics and non-bolometric photoresponse up to 30 K.

We achieve single and multi-photon detection regimes at 20 K as a function of the bias conditions of the nanowire

Such detectors are prime candidates for next generation quantum photonics.