PT Unknown
AU Sych, D
   Shcherbatenko, M
   Elezov, M
   Goltsman, GN
TI Towards the improvement of the heterodyne receiver sensitivity beyond the quantum noise limit
SE Proc. 29[super:th] Int. Symp. Space Terahertz Technol.
PY 2018
BP 245
EP 247
DE standard quantum limit; sub-SQL quantum receiver; Kennedy receiver; SSPD; SNSPD
AB Noise reduction in heterodyne receivers of the terahertz range is an important issue for astronomical applications. Quantum fluctuations, also known as shot noise, prohibit errorless measurements of the amplitude of electro-magnetic waves, and introduce the so-called standard quantum limit (SQL) on the minimum error of the heterodyne measurements. Nowadays, the sensitivity of modern heterodyne receivers approaches the SQL, and the growing demand for the improvement of measurement precision stimulates a number of both theoretical and experimental efforts to design novel measurement techniques aimed at overcoming the SQL. Here we demonstrate the first steps towards the practical implementation of a sub-SQL quantum receiver. As the principal resources, it requires a highly efficient single-photon counting detector and an interferometer-based scheme for mixing the signal with a low-power local oscillator. We describe the idea of such receiver and its main components.
ER