[show abstract][hide abstract] ABSTRACT: We describe quasi-optical SIS mixers operating in the submillimeter band (500-750 GHz) which have very low noise, around 5 hν/k<sub>B</sub> for the double-sideband receiver noise temperature. The mixers use a twin-slot antenna, Nb/Al-Oxide/Nb tunnel junctions fabricated with optical lithography, a two-junction tuning circuit, and a silicon hyperhemispherical lens with a novel antireflection coating to optimize the optical efficiency. We have flown a submillimeter receiver using these mixers on the Kuiper Airborne Observatory, and have detected a transition of H<sub>2</sub><sup>18</sup>O at 745 GHz. This directly confirms that SIS junctions are capable of low-noise mixing above the gap frequency.
IEEE Transactions on Appiled Superconductivity 07/1995; · 1.20 Impact Factor
[show abstract][hide abstract] ABSTRACT: We have constructed a sensitive submillimeter receiver for the NASA Kuiper Airborne Observatory (KAO) which at present operates in the 500-750 GHz band. The DSB receiver noise temperature is about 5 h nu/k(sub B) over the 500-700 GHz range. This receiver has been used to detect H2O(18)O, HCl, and CH in interstellar molecular clouds, and also to search for C(+) emission from the highly redshifted galaxy (z = 2.3) IRAS 10214.
[show abstract][hide abstract] ABSTRACT: We discuss airborne observations of rotational transitions of various hydride molecules in the interstellar medium, including H2O-18 and HCl. The detection of these transitions is now feasible with a new, sensitive submillimeter receiver which has been developed for the NASA Kuiper Airborne Observatory (KAO) over the past several years.