Quantum detector tomography of a superconducting nanostrip photon-number-resolving detector

Abstract

Superconducting nanostrip photon detectors have been used as single-photon detectors, which can discriminate only photons’ presence or absence. It has recently been found that they can discriminate the number of photons by analyzing the output signal waveform, and they are expected to be used in various fields, especially in optical-quantum-information processing. Here, we improve the photon-number-resolving performance for light with a high-average photon number by pattern matching of the output signal waveform. Furthermore, we estimate the positive-operator-valued measure of the detector by a quantum detector tomography. The result shows that the device has photon-number-resolving performance up to five photons without any multiplexing or arraying, indicating that it is useful as a photon-number-resolving detector.

Efficient backcasting search for optical quantum state synthesis

“…We numerically show that the optical GKP qubit can be prepared in polynomial time for the number of patterns of coefficients. Additionally, our method is more feasible in terms of the required detectors, since the numerical results show that the detected photon number by each detector is at most 2 which has been experimentally demonstrated already [52][53][54].…”

Generating Gottesman-Kitaev-Preskill qubit using a cross-Kerr interaction between a squeezed light and Fock states in optics

“…[42,44], and the experimental realization for the photon number resolving detector, a key role in Refs. [42,44], has been demonstrated [75][76][77]. In addition, the inverse of sign for the cross-Kerr interaction could be realized by using the measurement-induced interaction or Rubidium-based cross-Kerr medium [71].…”

Reducing g(2)(0) of a Parametric Down-Conversion Source via Photon-Number Resolution with Superconducting Nanowire Detectors

“…In order to resolve the number of photons contained in each measurement we follow a similar procedure as in Refs. [40,41]. In particular, the resistance induced in the nanowire due to the absorption of an optical wavepacket exhibits a photon-number dependence that can be resolved by examining the slope of the rising edge of the output signal.…”

“…The PNR ability of SNSPDs was further improved in Refs. [41] and [42], which employed a conventional single-pixel SNSPD system with a low-noise cryogenic amplifier, and a superconducting nanowire with a taper for impedance-matching, respectively. These works show that SNSPDs are not merely NPNR detectors, but rather fast and highly efficient photon-number resolving detectors, posing them as the ideal tool to realise HSPS.…”