Absolute calibration of analog detectors using stimulated parametric down conversion

Abstract

Spontaneous parametric down conversion has been largely exploited as a tool for absolute calibration of photon counting detectors, photomultiplier tubes or avalanche photodiodes working in the Geiger regime. In this work we investigate the extension of this technique from very low photon flux of the photon counting regime to the absolute calibration of analog photodetectors at higher photon flux. Moving towards a higher photon rate, i.e. at a high gain regime, the spontaneous parametric down conversion shows the intrinsic limitations of the method, while the stimulated parametric down conversion process, where a seed beam is properly injected into the crystal in order to increase the photon generation rate in the conjugate arm, allows us to work around this problem. A preliminary uncertainty budget is discussed.