Experimental demonstration of a novel superconducting photon-number resolving detector at telecom wavelengths

Abstract

ABSTRACT We present a novel configuration for a photon number resolving detector based on a series array of shunted superconducting nanowires, which has the potential to provide a high dynamic range. The first prototype of the detector consisting of four series elements is demonstrated with the ability to resolve up to four photons in an incident optical pulse at the telecommunicat ion wavelength window. Keywords: photon-number resolving detectors, superconducting single-photon detectors, quantum optics. 1. INTRODUCTION Standard linear optical detectors that generate an electrical response proportional to the intensity of the incident light have their maximum sensitivity in the few hundreds of photons range, limited by the amplifier noise. On the other hand, single photon detectors (SPDs), which are the most sensitive detectors, are strongly nonlinear: One or more photons result in the same output signal. The gap in between these two detection modes can be filled with photon number resolving (PNR) detectors, which have the sensitivity of SPDs and are able to determine the number of photons in a weak optical pulse. Such detectors are greatly desirable not only in the field of quantum information processing and quantum communication, but also in any application dealing with low light levels, such as fluorescence spectroscopy or optical time-domain reflect ometry. The existing appr oaches for realization of PNR detectors, especially in the telecom wavelength range do not meet all the essential requirements of most applications in terms of timing resolution, sensitivity, speed and dynamic range. In this work, we present a new PNR detector based on spatial multiplexing of nanowire superconducting single-photon detectors