Fig. 3: Single-photon detection by superconducting MgB2 microwires.
From: Single-photon detection using large-scale high-temperature MgB2 sensors at 20 K
a I-V curve for 5 μm MgB2 microwire detector measured at T = 20 K in the two-terminal configuration. b Photon count rate vs attenuation factor, at different powers of incident lights for 1 μm-wide MgB2 device at given Ib ≈ 0.98Isw and λ = 1.55 μm. Measurement shows linearity over five orders of magnitude in count rates. c Normalized PCR vs relative bias current for different wire widths measured in the microscale MgB2 devices at 20 K. d Photon and dark-count rate (DCR) of 1-μm wide detector as a function of the absolute bias current (Ib) at 20 K. e The PCR and DCR, normalized to its maximum value, as a function of the relative bias current, Ib/Isw, measured in 1-μm MgB2 detector at given temperatures T and 1550-nm wavelength (λ). Notably, the count rate at 3.7 K is approaching a saturation plateau that suggests the internal detection efficiency of absorbed photons is approaching 100%. f PCR vs Ib for different λ measured in 5-μm wide MgB2 device at T = 20 K.
