Superconducting Nanowire Single-Photon Detectors for Quantum Photonic Integrated Circuits on GaAs

Superconducting nanowire single-photon detectors (SNSPDs) are very promising as integrated detectors for future quantum photonic integrated circuits. In this work, main technological challenges for the integration of NbN based SNSPDs onto GaAs based phonic circuits are addressed. A new approach to improve the performance of meander style SNSPDs based on a variable thickness is introduced and the first full integration of a quantum photonic chip on a scalable monolithic platform is demonstrated

Superconducting Nanowire Single-Photon Detectors for Quantum Photonic Integrated Circuits on GaAs

Superconducting nanowire single-photon detectors (SNSPDs) are very promising as integrated detectors for future quantum photonic integrated circuits. In this work, main technological challenges for the integration of NbN based SNSPDs onto GaAs based phonic circuits are addressed. A new approach to improve the performance of meander style SNSPDs based on a variable thickness is introduced and the first full integration of a quantum photonic chip on a scalable monolithic platform is demonstrated

Large active-area superconducting microwire detector array with single-photon sensitivity in the near-infrared

Superconducting nanowire single photon detectors (SNSPDs) are the highest-performing technology for time-resolved single-photon counting from the UV to the near-infrared. The recent discovery of single-photon sensitivity in micrometer-scale superconducting wires is a promising pathway to explore for large active area devices with application to dark matter searches and fundamental physics experiments. We present 8-pixel $1 mm^2$ superconducting microwire single photon detectors (SMSPDs) with $1\,\mathrm{\mu m}$-wide wires fabricated from WSi and MoSi films of various stoichiometries using electron-beam and optical lithography. Devices made from all materials and fabrication techniques show saturated internal detection efficiency at 1064 nm in at least one pixel, and the best performing device made from silicon-rich WSi shows single-photon sensitivity in all 8 pixels and saturated internal detection efficiency in 6/8 pixels. This detector is the largest reported active-area SMSPD or SNSPD with near-IR sensitivity published to date, and the first report of an SMSPD array. By further optimizing the photolithography techniques presented in this work, a viable pathway exists to realize larger devices with $cm^2$-scale active area and beyond

ISL1 is a major susceptibility gene for classic bladder exstrophy and a regulator of urinary tract development.

Previously genome-wide association methods in patients with classic bladder exstrophy (CBE) found association with ISL1, a master control gene expressed in pericloacal mesenchyme. This study sought to further explore the genetics in a larger set of patients following-up on the most promising genomic regions previously reported. Genotypes of 12 markers obtained from 268 CBE patients of Australian, British, German Italian, Spanish and Swedish origin and 1,354 ethnically matched controls and from 92 CBE case-parent trios from North America were analysed. Only marker rs6874700 at the ISL1 locus showed association (p = 2.22 × 10-08). A meta-analysis of rs6874700 of our previous and present study showed a p value of 9.2 × 10-19. Developmental biology models were used to clarify the location of ISL1 activity in the forming urinary tract. Genetic lineage analysis of Isl1-expressing cells by the lineage tracer mouse model showed Isl1-expressing cells in the urinary tract of mouse embryos at E10.5 and distributed in the bladder at E15.5. Expression of isl1 in zebrafish larvae staged 48 hpf was detected in a small region of the developing pronephros. Our study supports ISL1 as a major susceptibility gene for CBE and as a regulator of urinary tract development

Pilots’ Willingness to Report Aviation Incidents

This paper reports results from a survey-based study among eighty-six airline pilots investigating their willingness to report safety-relevant events and incidents. Pilots have been asked to report how many events they have experienced in thirty-five different contextual areas and how often they have reported these cases. Thus, underreporting rates, respectively dark figures, were calculated and listed. These results and the willingness to report are discussed within an aviation operation’s background. Most of these surveyed underreporting rates are very high, which means a substantial source of uncertainty in airlines’ safety reporting databases, and thus for airlines’ safety management systems

Enhancing the performance of superconducting nanowire-based detectors with high-filling factor by using variable thickness

Current crowding at bends of superconducting nanowire single-photon detector (SNSPD) is one of the main factors limiting the performance of meander-style detectors with large filling factors. In this paper, we propose a new concept to reduce the influence of the current crowding effect, a so-called variable thickness SNSPD, which is composed of two regions with different thicknesses. A larger thickness of bends in comparison to the thickness of straight nanowire sections locally reduces the current density and reduces the suppression of the critical current caused by current crowding. This allows variable thickness SNSPD to have a higher critical current, an improved detection efficiency, and decreased dark count rate in comparison with a standard uniform thickness SNSPD with an identical geometry and film quality

Enhancing the performance of superconducting nanowire-based detectors with high-filling factor by using variable thickness

© 2021 IOP Publishing Ltd. Current crowding at bends of superconducting nanowire single-photon detector (SNSPD) is one of the main factors limiting the performance of meander-style detectors with large filling factors. In this paper, we propose a new concept to reduce the influence of the current crowding effect, a so-called variable thickness SNSPD, which is composed of two regions with different thicknesses. A larger thickness of bends in comparison to the thickness of straight nanowire sections locally reduces the current density and reduces the suppression of the critical current caused by current crowding. This allows variable thickness SNSPD to have a higher critical current, an improved detection efficiency, and decreased dark count rate in comparison with a standard uniform thickness SNSPD with an identical geometry and film quality