The possibility of absolute calibration of analog detectors by using parametric down-conver.pdfVIP

a r X i v : q u a n t - p h / 0 5 1 1 0 9 3 v 1 9 N o v 2 0 0 5 The possibility of absolute calibration of analog detectors by using parametric down-conversion: a systematical study Giorgio Brida1, Maria Chekhova2, Marco Genovese1, Alexander Penin2, Ivano Ruo-Berchera1 1 Istituto Elettrotecnico Nazionale Galileo Ferraris, Strada delle Cacce 91, 10135 Torino, Italy 2 Physics Department, M.V. Lomonosov State University, 119992 Moscow, Russia. In this paper we systematically study the possibility of the absolute calibration of analog photo- detectors based on the properties of parametric amplifiers. Our results show that such a method can be effectively developed with interesting possible metrological applications. PACS numbers: 42.50.Dv, 42.62.Eh, 03.67.-a; I. INTRODUCTION Accurate calibration of photodetectors both in ana- log and in photon-counting regime is fundamental for various scientific applications, which range from ”tra- ditional” quantum optics [1] to the studies on founda- tions of quantum mechanics [2], quantum cryptography [3], quantum computation [4], etc. In traditional optical radiometry primary standards are based on absolute sources or detectors [5]. Syn- chrotron and blackbody radiations are absolute sources. The spectral radiance of radiation emitted by electron storage rings can be predicted using the Schwinger equa- tion provided that the magnetic field and the electron current have been measured. In a similar way, the radiant flux emitted by a blackbody at a known thermodynamic temperature can be calculated from Planck’s equation. Both sources provide radiation with continuous spectral distribution, the dominant contribution being in the soft X-ray and UV spectral region for synchrotron radiation and in the IR spectral region for blackbody radiation. The relative uncertainty of both these sources is about 1 part in 103. Among the absolute detectors, there exist the following two types: thermal detector, called elec- trical substitution rad