Superconducting single-photon and photon-number-resolving detectors

Detecting light of low intensity is a key requirement in many fields of scientific endeavor, including but not limited to quantum information science, astronomy and optical spectroscopy. In the past decade the progress in the technology of superconducting film has allowed the realization of a new type of detector based on ultrathin (4-5nm) and narrow

Physics and application of photon number resolving detectors based on superconducting parallel nanowires

The Parallel Nanowire Detector (PND) is a photon number resolving (PNR) detector which uses spatial multiplexing on a subwavelength scale to provide a single electrical output proportional to the photon number. The basic structure of the PND is the parallel connection of several NbN superconducting nanowires (100 nm-wide, few nm-thick), folded in a meander pattern. PNDs were fabricated on 3-4 nm thick NbN films grown on MgO (TS=400C) substrates by reactive magnetron sputtering in an Ar/N2 gas mixture. The device performance was characterized in terms of speed and sensitivity. PNDs showed a counting rate of 80 MHz and a pulse duration as low as 660ps full width at half maximum (FWHM). Building the histograms of the photoresponse peak, no multiplication noise buildup is observable. Electrical and optical equivalent models of the device were developed in order to study its working principle, define design guidelines, and develop an algorithm to estimate the photon number statistics of an unknown light. In particular, the modeling provides novel insight of the physical limit to the detection efficiency and to the reset time of these detectors. The PND significantly outperforms existing PNR detectors in terms of simplicity, sensitivity, speed, and multiplication noise

Cavity-enhanced superconducting single-photon detectors on GaAs substrate

Nanowire superconducting single photon detectors (SSPDs) are unique detectors for many applications in quantum information and communications technology, owing to their ultrafast photoresponse, low dark count rate and low timing jitter. However, they have limited detection efficiency due to small optical absorption in ultrathin wires. A promising approach to increase the photon absorption in SSPDs, is integrating them with advanced optical structures. We demonstrate the successful integration of SSPDs with optical microcavities based on GaAs/AlAs Bragg mirrors. Characterization of these devices reveals clear cavity enhancement of the detection efficiency, resulting in a peak value of18% at 2=l300nm and T=4.2

Waveguide single-photon detectors for integrated quantum photonic circuits

The generation, manipulation and detection of quantum bits (qubits) encoded on single photons is at the heart of quantum communication and optical quantum information processing. The combination of single-photon sources, passive optical circuits and single-photon detectors enables quantum repeaters and qubit amplifiers, and also forms the basis of all-optical quantum gates and of linear-optics quantum computing. However, the monolithic integration of sources, waveguides and detectors on the same chip, as needed for scaling to meaningful number of qubits, is very challenging, and previous work on quantum photonic circuits has used external sources and detectors. Here we propose an approach to a fully-integrated quantum photonic circuit on a semiconductor chip, and demonstrate a key component of such circuit, a waveguide single-photon detector. Our detectors, based on superconducting nanowires on GaAs ridge waveguides, provide high efficiency (20%) at telecom wavelengths, high timing accuracy (60 ps), response time in the ns range, and are fully compatible with the integration of single-photon sources, passive networks and modulators.Comment: 11 pages, 4 figure

Towards linear optical detection with single photon sensitivity at telecom wavelengths

Standard linear optical detectors have a maximum sensitivity in the few hundreds of photons range, limited by amplifier noise. On the other hand, single photon detectors, which are the most sensitive detectors, are strongly nonlinear: One or more photons result in the same output signal. Photon number resolving (PNR) detectors, which have the ability to discriminate the number of photons in a weak optical pulse, are of great importance in the field of quantum information processing and quantum cryptography. Moreover, a PNR detector with large dynamic range can cover the gap between these two detection modes. Such detectors are greatly desirable not only in quantum information science and technology, but also in any application dealing with low light levels. In this work, we propose a novel approach to photon number resolving detectors based on spatial multiplexing of nanowire superconducting single-photon detectors. In the proposed approach, N superconducting nanowires, each connected in parallel to an integrated resistor, are connected in series. Photon absorption in a nanowire switches its bias current to the parallel resistor, forming a voltage pulse across it. The sum of these voltages, proportional to the number of absorbed photons, is measured at the output. The use of a cryogenic preamplifier with high input impedance for the read-out increases the linearity, the signal to noise ratio, and the speed. With this combination, we expect to be able to count up to few tens of photons with high fidelity, excellent timing resolution, and very high sensitivity in the telecommunication wavelength range

Proposal for a superconducting photon number resolving detector with large dynamic range

We propose a novel photon number resolving detector structure with large dynamic range. It consists of the series connection of N superconducting nanowires, each connected in parallel to an integrated resistor. Photon absorption in a wire switches its current to the parallel resistor producing a voltage pulse and the sum of these voltages is measured at the output. The combination of this structure and a high input impedance preamplifier result in linear, high fidelity, and fast photon detection in the range from one to several tens of photons

Towards linear optical detection with single photon sensitivity at telecommunication wavelengths

The conventional optical detectors operate in a linear mode, but their sensitivity is limited due to the noise in the readout electronics. Single photon detectors, on the other hand, have the highest sensitivity, but are strongly nonlinear. Photon number resolving detectors, which can precisely determine the number of photons in weak optical pulses, are potential candidates to fill the gap between these two detection modes. We present the design of photon number resolving detectors with large dynamic range, based on spatial multiplexing of superconducting single photon detectors, with excellent timing resolution and very high sensitivity at the telecommunication wavelength range

Proposal for a superconducting photon number resolving detector with large dynamic range

We propose a novel photon number resolving detector structure with large dynamic range. It consists of the series connection of N superconducting nanowires, each connected in parallel to an integrated resistor. Photon absorption in a wire switches its current to the parallel resistor producing a voltage pulse and the sum of these voltages is measured at the output. The combination of this structure and a high input impedance preamplifier result in linear, high fidelity, and fast photon detection in the range from one to several tens of photons

Towards linear optical detection with single photon sensitivity at telecommunication wavelengths

The conventional optical detectors operate in a linear mode, but their sensitivity is limited due to the noise in the readout electronics. Single photon detectors, on the other hand, have the highest sensitivity, but are strongly nonlinear. Photon number resolving detectors, which can precisely determine the number of photons in weak optical pulses, are potential candidates to fill the gap between these two detection modes. We present the design of photon number resolving detectors with large dynamic range, based on spatial multiplexing of superconducting single photon detectors, with excellent timing resolution and very high sensitivity at the telecommunication wavelength range

Waveguide photon-number-resolving detectors for quantum photonic integrated circuits

Quantum photonic integration circuits are a promising approach to scalable quantum processing with photons. Waveguide single-photon-detectors (WSPDs) based on superconducting nanowires have been recently shown to be compatible with single-photon sources for a monolithic integration. While standard WSPDs offer single-photon sensitivity, more complex superconducting nanowire structures can be configured to have photon-number-resolving capability. In this work, we present waveguide photon-number-resolving detectors (WPNRDs) on GaAs/Al0.75Ga0.25As ridge waveguides based on a series connection of nanowires. The detection of 0-4 photons has been demonstrated with a four-wire WPNRD, having a single electrical read-out. A device quantum efficiency of similar to 24% is reported at 1310 nm for the transverse electric polarization. (C) 2013 AIP Publishing LLC.Publisher PDFPeer reviewe