Browsing by Author "Luukanen, Arttu R."
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- Fluctuation-Limited noise in a superconducting transition-edge sensor
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2003-06-13) Luukanen, Arttu R.; Kinnunen, K.M.; Nuottajärvi, A.K.; Hoevers, H.F.C.; Bergmann Tiest, W.M.; Pekola, JukkaIn order to investigate the origin of the until now unaccounted excess noise and to minimize the uncontrollable phenomena at the transition in x-ray microcalorimeters we have developed superconducting transition-edge sensors into an edgeless geometry, the so-called Corbino disk, with superconducting contacts in the center and at the outer perimeter. The measured rms current noise and its spectral density can be modeled as resistance noise resulting from fluctuations near the equilibrium superconductor-normal metal boundary. - Millimeter wave imaging at up to 40 frames per second using an optoelectronic photo-injected Fresnel zone plate lens antenna
A4 Artikkeli konferenssijulkaisussa(2016-01-01) Robertson, Duncan A.; Gallacher, Thomas F.; Søndenå, Rune; Macfarlane, David G.Optoelectronic methods are promising for rapid and highly reconfigurable beam steering across the microwave to the terahertz range. In particular, the photo-injected Fresnel zone plate antenna (piFZPA) offers high speed, wide angle, precise beam steering with good beam quality, to enable video rate millimeter wave imagery with no moving parts. We present a piFZPA demonstrator based on a commercial digital light projector (DLP) and high power laser which achieves steering rates up to 17,500 beams per second at 94 and 188 GHz. We also demonstrate radar imaging at 94 GHz at frame rates of 40 Hz (2D PPI) and 7 Hz (3D volumetric).