[show abstract][hide abstract] ABSTRACT: We have measured the quantum efficiency (QE), GHz counting rate, jitter, and noise-equivalent power (NEP) of nanostructured NbN superconducting single-photon detectors (SSPDs) in the visible to infrared radiation range. Our 3.5-nm-thick and 100- to 200-nm-wide meander-type devices (total area 10×10 μm2), operating at 4.2 K, exhibit an experimental QE of up to 20% in the visible range and ∼ 10% at 1.3 to 1.55 μm wavelength and are potentially sensitive up to midinfrared ( ∼ 10 μm) radiation. The SSPD counting rate was measured to be above 2 GHz with jitter <18 ps, independent of the wavelength. The devices’ NEP varies from ∼ 10−17 W/Hz1/2 for 1.55 μm photons to ∼ 10−20W/Hz1/2 for visible radiation. Lowering the SSPD operating temperature to 2.3 K significantly enhanced its performance, by increasing the QE to ∼ 20% and lowering the NEP level to ∼ 3×10−22 W/Hz1/2, both measured at 1.26 μm wavelength.
[show abstract][hide abstract] ABSTRACT: In this paper, a novel, time-resolved, NbN-based, superconducting single-photon detector (SSPD) has been developed for probing CMOS integrated circuits (ICs) using photon emission timing analysis (PETA).
Lasers and Electro-Optics Society, 2003. LEOS 2003. The 16th Annual Meeting of the IEEE; 11/2003
[show abstract][hide abstract] ABSTRACT: The 3.5 nm thick-film, meander-structured NbN superconducting single-photon detectors have been implemented in the CMOS circuit-testing system based on the detection of near-infrared photon emission from switching transistors and have significantly improved the performance of the system. Photon emissions from both p- and n-MOS transistors have been observed.
[show abstract][hide abstract] ABSTRACT: We present a new class of ultrafast single-photon detectors for counting both visible and infrared photons. The detection mechanism is based on photon-induced hotspot formation, which forces the supercurrent redistribution and leads to the appearance of a transient resistive barrier across an ultrathin, submicrometer-width, superconducting stripe. The devices were fabricated from 3.5-nm- and 10-nm-thick NbN films, patterned into <200-nm-wide stripes in the 4 × 4-μm<sup>2</sup> or 10 × 10-μm<sup>2</sup> meander-type geometry, and operated at 4.2 K, well below the NbN critical temperature (T<sub>c</sub>=10-11 K). Continuous-wave and pulsed-laser optical sources in the 400-nm-to 3500-nm-wavelength range were used to determine the detector performance in the photon-counting mode. Experimental quantum efficiency was found to exponentially depend on the photon wavelength, and for our best, 3.5-nm-thick, 100-μm<sup>2</sup>-area devices varied from >10% for 405-nm radiation to 3.5% for 1550-nm photons. The detector response time and jitter were ∼100 ps and 35 ps, respectively, and were acquisition system limited. The dark counts were below 0.01 per second at optimal biasing. In terms of the counting rate, jitter, and dark counts, the NbN single-photon detectors significantly outperform their semiconductor counterparts. Already-identified applications for our devices range from noncontact testing of semiconductor CMOS VLSI circuits to free-space quantum cryptography and communications.
IEEE Transactions on Appiled Superconductivity 07/2003; · 1.20 Impact Factor