A linear-optics quantum computer 5 requires hundreds to thousands of single-photon components including sources, detectors and interferometers, which is obviously only feasible in an integrated circuit.Even the small-scale circuits needed in quantum repeaters 2 would greatly benefit from monolithic integration in view of the improved stability and coupling efficiency attainable in a chip. A very large experimental research activity has been dedicated to the development of single-photon sources based on III-V semiconductors 10 , in view of large-scale integration, and to passive quantum circuits based on silica-onsilicon 6 and on laser-micromachined glass 8,9 , but a clear approach towards a fully integrated photonic network including sources and detectors has not been proposed. This is in large part due to the complexity of most single-photon detector technologies -for example, the complex device structures associated to avalanche photodiodes are not easily compatible with the integration of low-loss waveguides and even less of sources. Transition-edge sensors may be suited for integration 11 , but they are plagued by very slow response times (leading to maximum counting rates in the tens of kHz range) and require cooling down to <100 mK temperatures. Here we propose a platform for the full integration of quantum photonic components on the same chip. It is based on the mature III-V semiconductor technology and comprises ( Fig. 1(a) ) waveguide single-photon sources based on InAs quantum dots (QDs), GaAs/AlGaAs ridge waveguides, Mach-Zehnder interferometers using directional couplers or multimode-interference couplers, and 3 waveguide detectors based on superconducting nanowires. Efficient single-photon emission from QDs in a waveguide can be obtained by using photonic crystals (PhCs), e.g. in a cavity side-coupled to a waveguide 12 or using the slow-light regime in PhC waveguides 13 , and the photons can then be transferred to ridge waveguides using tapers. Photons emitted by distinct QDs can be made indistinguishable by using electric fields to control the exciton energy 14 . The high index contrast available in the GaAs/AlGaAs system allows circuits with short bending radii, therefore more compact than in the silica platform 6 , while the large electrooptic coefficient of GaAs enables compact modulators operating at GHz frequencies. In this letter we report the key missing component, a single-photon detector integrated with GaAs waveguides. Our waveguide single-photon detectors (WSPDs) are based on the principle of photon-induced hot-spot creation in ultranarrow superconducting NbN wires, which is also used in nanowire superconducting single-photon detectors 15 (SSPDs) and can provide ultrahigh sensitivity at telecommunication wavelengths, high counting rates, broad spectral response and high temporal resolution due to low jitter values. In our design (see Fig. 1(b)), the wires are deposited and patterned on top of a GaAs ridge waveguide, in order to sense the evanescent field on the surface. Four NbN nanowi...
Abstract:We present an experimental method to characterize multiphoton detectors with a small overall detection efficiency. We do this by separating the nonlinear action of the multiphoton detection event from linear losses in the detector. Such a characterization is a necessary step for quantum information protocols with single and multiphoton detectors and can provide quantitative information to understand the underlying physics of a given detector. This characterization is applied to a superconducting multiphoton nanodetector, consisting of an NbN nanowire with a bowtie-shaped subwavelength constriction. Depending on the bias current, this detector has regimes with single and multiphoton sensitivity. We present the first full experimental characterization of such a detector. Berggren, "Photon-number-resolution with sub-30-ps timing using multi-element superconducting nanowire single photon detectors," J. Mod. Optic. 56, 13 (2008).
We present the experimental demonstration of a superconducting photon number resolving detector. It is based on the series connection of N superconducting nanowires, each connected in parallel to an integrated resistor. The device provides a single voltage readout, proportional to the number of photons absorbed in distinct nanowires. Clearly separated output levels corresponding to the detection of n=1-4 photons are observed in a 4-element detector fabricated from an NbN film on GaAs substrate, with a single-photon system quantum efficiency of 2.6% at =1.3m. The series-nanowire structure is promising in view of its scalability to large photon numbers and high efficiencies.Conventional optical detectors generate an electrical signal proportional to the intensity of the incident light. However their sensitivity is limited by the electrical noise in the amplification circuit. On the other hand, single photon detectors (SPDs), which are extremely sensitive devices, usually show a strongly nonlinear response, i.e. their output signal level is independent of the number of photons that simultaneously hit the detector. The gap between these two detection regimes can be filled with a photon-number-resolving (PNR) detector, a device as sensitive as an SPD, and with a capability of precisely determining the number of photons that
Using detector tomography, we investigate the detection mechanism in NbN-based superconducting single photon detectors (SSPDs). We demonstrate that the detection probability uniquely depends on a particular linear combination of bias current and energy, for a large variation of bias currents, input energies and detection probabilities, producing a universal detection curve. We obtain this result by studying multiphoton excitations in a nanodetector with a sparsity-based tomographic method that allows factoring out of the optical absorption. We discuss the implication of our model system for the understanding of meander-type SSPDs.
In this article we have investigated two important properties of metallic nano-resonators which can substantially improve the temperature performances of infrared quantum detectors. The first is the antenna effect that increases the effective surface of photon collection and the second is the subwavelength metallic confinement that compresses radiation into very small volumes of interaction. To quantify our analysis we have defined and discussed two figures of merit, the collection area A coll and the focusing factor F. Both quantities depend solely on the geometrical parameters of the structure and can be applied to improve the performance of any detector active region. In the last part, we describe three-dimensional electronic nano-resonators that provide highly subwavelength confinement of the electromagnetic energy, beyond the microcavity limits and illustrate that these device architectures have a tremendous potential to increase the temperature of operation of infrared quantum detectors.Plasmonic nanostructures constitute an important and attractive research topic in the domain of photonics and nano-electronics [1,2]. They are widely investigated in different ranges of the electromagnetic spectrum, starting from the visible [3,4], through the infrared [5, 6] and down to the terahertz frequencies [7,8]. Plasmonic nanostructure have been already exploited as an efficient mean to compress light in a sub-wavelength region of the space [7,9] in order to improve the performances of optoelectronic devices, both as efficient absorbers [10][11][12][13][14][15][16][17][18][19] or emitters [20][21][22][23]. In particular, a fundamental property of a resonant absorber, such as plasmonic nanoparticle, is its ability to gather photons from a collection area A coll that can be much larger than its geometrical cross section σ [24], as illustrated in figure 1. The ultimate limit of this phenomenon is found in the quantum transition of a single atom at the resonant wavelength λ, where A coll can be identified with an absorption cross section A coll =3λ 2 /4π [25]. While this concept is widely used in antenna-coupled devices in the low-frequency part of the electromagnetic spectrum [26], it is clearly underexploited for infrared and optical quantum detectors of radiation. In particular, we have recently illustrated that in the mid-infrared and THz frequencies ranges, antenna-coupled quantum well infrared photo-detectors (QWIPs) can lead to a substantial reduction of the dark current with respect to the photocurrent signal [15,16]. High temperature, high performance photodetectors in the mid-and far-infrared is an actual issue that would enable the realization of sensitive thermal imaging setups with a broad range of applications [27]. Resonant structures, such as cavities and photonic cristals have already been envisioned for the enhancement for both intrasubband [28] and intersubband photodetectors [20,29], however in these studies the antenna effect was not taken into account.In the current work, we provide a quantitative...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.