Two-dimensional cuprate nanodetector with single telecom photon sensitivity at T = 20 K

Abstract Detecting light at the single-photon level is one of the pillars of emergent photonic technologies. This is realized through state-of-the-art superconducting detectors that offer efficient, broadband and fast response. However, the use of low T C superconducting thin films limits their operation temperature to approximately 4 K and below. Here, we demonstrate proof-of-concept nanodetectors based on exfoliated, two-dimensional cuprate superconductor Bi 2 Sr 2 CaCu 2 O 8- δ that exhibit single-photon sensitivity at telecom wavelength at a record temperature of T = 20 K. These non-optimized devices exhibit a slow <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mfenced close=")" open="("> <mml:mrow> <mml:mo>∼</mml:mo> <mml:mtext> </mml:mtext> <mml:mrow> <mml:mrow> <mml:mi>m</mml:mi> <mml:mi>s</mml:mi> </mml:mrow> </mml:mrow> </mml:mrow> </mml:mfenced> </mml:math> reset time and a low detection efficiency ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>∼</mml:mo> <mml:mrow> <mml:msup> <mml:mn>10</mml:mn> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>4</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> ). We realize the elusive prospect of single-photon sensitivity on a high- T C nanodetector thanks to a novel approach, combining van der Waals fabrication techniques and a non-invasive nanopatterning based on light ion irradiation. This result paves the way for broader application of single-photon technologies, relaxing the cryogenic constraints for single-photon detection at telecom wavelength.