5 research outputs found
Single photon source characterization with a superconducting single photon detector
Superconducting single photon detectors (SSPD) based on nanopatterned niobium
nitride wires offer single photon counting at fast rates, low jitter, and low
dark counts, from visible wavelengths well into the infrared. We demonstrate
the first use of an SSPD, packaged in a commercial cryocooler, for single
photon source characterization. The source is an optically pumped,
microcavity-coupled InGaAs quantum dot, emitting single photons on demand at
902 nm. The SSPD replaces the second silicon Avalanche Photodiode (APD) in a
Hanbury-Brown Twiss interferometer measurement of the source second-order
correlation function, g (2) (tau). The detection efficiency of the
superconducting detector system is >2 % (coupling losses included). The SSPD
system electronics jitter is 170 ps, versus 550 ps for the APD unit, allowing
the source spontaneous emission lifetime to be measured with improved
resolution.Comment: 8 page
Production of very-high-amylose potato starch by inhibition of SBE A and B
High-amylose starch is in great demand by the starch industry for its unique functional properties. However, very few high-amylose crop varieties are commercially available. In this paper we describe the generation of very-high-amylose potato starch by genetic modification. We achieved this by simultaneously inhibiting two isoforms of starch branching enzyme to below 1% of the wild-type activities. Starch granule morphology and composition were noticeably altered. Normal, high-molecular-weight amylopectin was absent, whereas the amylose content was increased to levels comparable to the highest commercially available maize starches. In addition, the phosphorus content of the starch was increased more than fivefold. This unique starch, with its high amylose, low amylopectin, and high phosphorus levels, offers novel properties for food and industrial applications