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A bright nanowire single photon source

A bright nanowire single photon source

A bright nanowire single photon source The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. Citation Marseglia, L., et al. “A Bright Nanowire Single Photon Source.” Conference on Lasers and Electro-Optics, 5-10 June 2016, San Jose, California, OSA, 2016, p. FTu3D.1.

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Polarization entangled photon-pair source based on quantum nonlinear photonics and interferometry

Polarization entangled photon-pair source based on quantum nonlinear photonics and interferometry

Our source specifications are outlined in the following. First, the paired photons are emitted at a wavelength lying in the telecom C-band (1530 - 1565 nm), and further collected using a single mode telecom fiber in order to benefit from both standard components for routing and filtering purposes and low propagation losses in case of distribution over a long distance. Second, the photon bandwidth is made readily adaptable so as to be compatible with a broad variety of applications, ranging from QKD in telecommunication channels to quantum storage device implementations. Third, the coding of quantum information relies on the polarization observable since entanglement correlations can be measured using simple analyzers, being free of interferometric devices as opposed to the case of the time-bin observable [35]. In addition, polarization entanglement can now be distributed over long distances thanks to active compensation systems of fiber birefringence fluctuations [36]. Eventually, and importantly, the key figures of merit are a high rate of available photon-pairs, and a fidelity to the desired entangled state as close to unity as possible.
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High photon flux Kα Mo x-ray source driven by a multi-terawatt femtosecond laser at 100 Hz

High photon flux Kα Mo x-ray source driven by a multi-terawatt femtosecond laser at 100 Hz

applications, the key parameters are a high photon flux, a point- like x-ray source, and an ultrashort x-ray pulse duration. To get access to these characteristics and, especially, to reach a high photon flux per shot, operation of the driving laser at high in- tensity is needed [ 7 ], requiring the use of multi-terawatt femtosecond laser sources. The efficient generation of K α hard x-ray photons (>10 keV) necessitates even higher intensity when the atomic number Z of the target increases, as empiri- cally scaled [ 8 ]. A high repetition rate of the driving laser pulse is also an important parameter to reduce the time exposure or the dose delivered while accessing to suitable (high) and flexible signal-to-noise and contrast-to-noise ratios for applications in the context of medical imaging [ 9 ] or material science [ 10 ]. Many research groups developed K α sources at a high repeti- tion rate reaching 1 kHz [ 3 , 11 ]. However, these systems are limited in laser energy per pulse which precludes the delivery of high intensity on target and, thus, reduces the conversion efficiency and the total hard x-ray flux [ 7 , 12 ]. At the opposite, high-energy ultrashort laser sources are limited to a low repeti- tion rate [ 12 , 13 ] which is an obstacle when time exposure or sensitivity to x-ray peak dose is a concern. In this Letter, we propose to pave an intermediate way combining a mid- x-ray dose per pulse, requiring multi-terawatt driving laser system, and a relatively high repetition rate (>10 Hz) for deliv- ering high average power and high brightness x-ray sources which are suitable for many applications. Thereby, we demon- strate an unrivalled performance in terms of the average photon flux of an intense K α hard x-ray (17.4 keV) source generated with a unique laser system delivering intermediate energy per pulse (∼ up to 122 mJ on target) and an ultrashort pulse du- ration ( ∼25 fs) at the relatively high repetition rate of 100 Hz. Finally, the characteristics of the present Mo K α x-ray laser plasma source are compared with those published to date.
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Polarization entangled photon-pair source based on a type-II PPLN waveguide emitting at a telecom wavelength

Polarization entangled photon-pair source based on a type-II PPLN waveguide emitting at a telecom wavelength

E-mail: sebastien.tanzilli@unice.fr Abstract. We report the realization of a fiber coupled polarization entangled photon-pair source at 1310 nm based on a birefringent titanium in-diffused waveguide integrated on periodically poled lithium niobate. By taking advantage of a dedicated and high-performance setup, we characterized the quantum properties of the pairs by measuring two-photon interference in both Hong-Ou-Mandel and standard Bell inequality configurations. We obtained, for the two sets of measurements, interference net visibilities reaching nearly 100%, which represent important and competitive results compared to similar waveguide-based configurations already reported. These results prove the relevance of our approach as an enabling technology for long-distance quantum communication.
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A high-fidelity single-photon source based on a type-II optical parametric oscillator

A high-fidelity single-photon source based on a type-II optical parametric oscillator

OCIS codes: 270.0270, 270.6570, 270.5290,190.4970 The reliable generation of single-photon states is a cen- tral resource for the development of quantum informa- tion sciences and technologies, including quantum com- munication and computing [1, 2]. For instance, since the seminal proposal by Knill, Laflamme and Milburn [3], single-photons are indeed at the heart of linear-optical quantum computation (LOQC) [4]. Practical implemen- tations however require to generate such states with a low admixture of vacuum as efficient LOQC protocols are constrained by loss thresholds [5]. For instance, the best known figure to date, which applies to cluster state computation, is a 1/2 overall loss tolerance [6], i.e. the product of the source fidelity and detector efficiency has to be above this value. This constraint puts a chal- lenging demand on single-photon generation. Addition- ally, linear-optical processing cannot increase the fidelity of the state, even with multiple imperfect sources [7]. Moreover, gate implementation requires to make single- photons interfere with a high visibility and thus to be emitted into a well-controlled spatiotemporal mode.
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Highly efficient photon-pair source using a periodically poled lithium niobate waveguide

Highly efficient photon-pair source using a periodically poled lithium niobate waveguide

account 15% coupling of the pump into the guide, less than 1 µW is used to create the photon pairs. Our first figure of merit is the ratio of coincidence rate (R C ) to pump power (P P ). As shown in table 1, our source features the same order of magnitude for the coincidence rate using 10 3 times less pump power than other sources reported lately [3,5,13,14].

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Bright nanoscale source of deterministic entangled photon pairs violating Bell’s inequality

Bright nanoscale source of deterministic entangled photon pairs violating Bell’s inequality

Methods Comparison of diferent entangled photon-pair sources. To make a comparison between diferent types of polarization-entangled photon-pair sources a common basis has to be found. We chose to compare the idelity to a maximally entangled state as a function of the photon-pair source eiciency. For the quantum dot related publications the eiciency is given as the average number of photon pairs per excitation pulse collected into the irst lens, whereas for the parametric down-conversion sources it is the same igure of merit but collected into the irst iber. he photon-pair source eiciency includes the collection eiciency and the pair generation eiciency. In quantum dot studies the source eiciency is typically calculated from the excitation pulse rate, the setup eiciency and the count rates on the detectors. It directly includes the internal pair generation eiciency of the investigated quantum dot. he pair generation eiciency varies from dot to dot, due to diferent recombina- tion channels, and depends on the excitation conditions. For parametric down-conversion sources the internal pair generation eiciency depends on the excitation power. Due to the probabilistic nature of the generation, higher excitation power also leads to multi-pair generation reducing the source idelity. In Fig.  6 we only compare idelities from pulsed sources and the quantum dot based data were all obtained without additional temporal post-selection. For each cited work an explanation of how the data points for Fig.  6 were obtained is given below:
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Polarization entangled photon-pair source based on quantum nonlinear photonics and interferometry

Polarization entangled photon-pair source based on quantum nonlinear photonics and interferometry

‡ Currently with the Group of Applied Physics, University of Geneva, Switzerland Abstract We present a versatile, high-brightness, guided-wave source of polarization entangled photons, emitted at a tele- com wavelength. Photon-pairs are generated using an integrated type-0 nonlinear waveguide, and subsequently prepared in a polarization entangled state via a stabilized fiber interferometer. We show that the single photon emission wavelength can be tuned over more than 50 nm, whereas the single photon spectral bandwidth can be chosen at will over more than five orders of magnitude (from 25 MHz to 4 THz). Moreover, by performing entanglement analysis, we demonstrate a high degree of control of the quantum state via the violation of the Bell inequalities by more than 40 standard deviations. This makes this scheme suitable for a wide range of quantum optics experiments, ranging from fundamental research to quantum information applications.
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Multiplexed single-photon source based on multiple quantum dots embedded within a single nanowire

Multiplexed single-photon source based on multiple quantum dots embedded within a single nanowire

Cite This: Nano Lett. 2020, 20, 3688−3693 Read Online ACCESS Metrics & More Article Recommendations ABSTRACT: Photonics-based quantum information technologies require efficient, high emission rate sources of single photons. Position-controlled quantum dots embedded within a broadband nanowire waveguide provide a fully scalable route to fabricating highly efficient single-photon sources. However, emission rates for single-photon devices are limited by radiative recombination lifetimes. Here, we demonstrate a multiplexed single-photon source based on a multidot nanowire. Using epitaxially grown nanowires, we incorporate multiple energy-tuned dots, each optimally positioned within the nanowire waveguide, providing single photons with high efficiency. This linear scaling of the single-photon emission rate with number of emitters is demonstrated using a five-dot nanowire with an average multiphoton emission probability of <4% when excited at saturation. This represents the first ever demonstration of multiple single-photon emitters deterministically incorporated in a single
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High performance guided-wave asynchronous heralded single photon source

High performance guided-wave asynchronous heralded single photon source

We report on a guided wave asynchronous heralded single photon source based on the creation of non- degenerate photon pairs by spontaneous parametric down conversion in a Periodically Poled Lithium Niobate waveguide. We show that using the signal photon at 1310 nm as a trigger, a gated detection process permits announcing the arrival of single photons at 1550 nm at the output of a single mode optical fiber with a high probability of 0.37. At the same time the multi-photon emission probability is reduced by a factor of 10 compared to poissonian light sources. Furthermore, the model we have developed to calculate those figures of merit is shown to be very accurate. This study can therefore serve as a paradigm for the conception of new quantum communication and computation networks. 2010 Optical Society of America c
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Ultra-fast heralded single photon source based on telecom technology

Ultra-fast heralded single photon source based on telecom technology

compiled: June 25, 2015 The realization of an ultra-fast source of heralded single photons emitted at the wavelength of 1540 nm is reported. The presented strategy is based on state-of-the-art telecom technology, combined with off-the-shelf fiber components and waveguide non-linear stages pumped by a 10 GHz repetition rate laser. The single photons are heralded at a rate as high as 2.1 MHz with a heralding efficiency of 42%. Single photon character of the source is inferred by measuring the second-order autocorrelation function. For the highest heralding rate, a value as low as 0.023 is found. This not only proves negligible multi-photon contributions but also represents the best measured value reported to date for heralding rates in the MHz regime. These prime performances, associated with a device-like configuration, are key ingredients for both fast and secure quantum communication protocols.
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Toward an operationnal single photon source based on semiconductor nanowires

Toward an operationnal single photon source based on semiconductor nanowires

L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignemen[r]

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A solid state source of photon triplets based on quantum dot molecules

A solid state source of photon triplets based on quantum dot molecules

triplet generation employing SPDC under pulsed pumping by an order of magnitude 37 . Discussion Creating entangled photon triplets, as opposed to time correlated ones, remains as the next-step study goal to our present observations. The prospects of tripartite photon entanglement include, but are not limited to, multipartite quantum secret sharing, other quantum communication protocols 38,39 and third party cryptography. As a relevant example, tripartite time-bin entanglement 40 could be realized using the spin states of a triexciton bound in a QDM. Time-bin encoding has a clear benefit for long distance quantum communication through optical fibres because the relative phase between each two pulses with a few nanosecond temporal spacing is merely susceptible to a medium varying faster than this timescale. Implementing this kind of entanglement in a QDM, however, demands resonant pumping of the triexciton to encode the laser phase onto the emitted photon triplet in a relatively dephasing- free process 16 . In contrast to incoherent, pulsed excitation, almost a complete elimination of background light is expected under resonant pumping, and due to the absence of additional intraband relaxation processes the time jitter will be limited to the exciton radiative lifetime. In analogy with single quantum dots, coherent pulsed excitation of a QDM could prepare the triexciton in either of the singlet and triplet spin states, 0 XX,L , S R
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Single-photon Sagnac interferometer

Single-photon Sagnac interferometer

5. Conclusion We have presented the first experimental demonstration of the Sagnac effect using light at the quantum level. The homemade heralded single-photon source at 1550 nm we use is based on guided-wave spontaneous parametric down conversion in a periodically-poled lithium niobate waveguide. The use of a fibred interferometer and the control of the polarization state allow us to let the source, detectors and electronics motionless. This double path quantum interference shows a fringe visibility greater than 99%. While this setup cancels the detrimental nonlinear effects present in fibre optics gyroscope, the required integration time seems to limit the interest of the single-photon Sagnac interferometer for such gyroscopes.
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Triarylisocyanurate-Based Fluorescent Two-Photon Absorbers

Triarylisocyanurate-Based Fluorescent Two-Photon Absorbers

corrections. [34] Reference values between 700 and 715 nm for fluorescein were taken from literature. [35] The quadratic dependence of the fluorescence intensity on the excitation power was checked for each sample and all wavelengths. Measurements were conducted using an excitation source delivering fs pulses. A Chameleon Ultra II (Coherent) was used generating 140 fs pulses at 80 MHz repetition rate. The excitation was focused into the cuvette through a microscope objective (10X, NA 0.25). The fluorescence was detected in epifluorescence mode via a dichroic mirror (Chroma 675dcxru) and a barrier filter (Chroma e650sp-2p) by a compact CCD spectrometer module BWTek BTC112E. Total fluorescence intensities were obtained by integrating the corrected emission.
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A single-photon fluorescence and multi-photon spectroscopic study of atherosclerotic lesions

A single-photon fluorescence and multi-photon spectroscopic study of atherosclerotic lesions

2.3 Multi-photon spectra and image acquisition Samples were also investigated using a home built multi-photon laser scanning microscope modified to allow spectral acquisition. A schematic of the modified microscope system is provided in Figure 2. The laser source comprised a 532 nm laser (Spectra-Physics, USA) operating at 7.25 W pumping a Ti:Sapphire oscillator (Spectra-Physics, USA). Output pulses from the oscillator were centered at 800 nm with a pulse width of ~100 fs and average power of 1.1 W. The output femto-second laser pulses were passed through a Faraday isolator (Newport, USA) and a pair of GTI laser mirrors (Layertec GmbH, Germany) then split into “pump” and “Stokes” pulses using a 50/50 beam splitter. The reflected pump pulses propagated through a series of lenses and mirrors including an optical delay stage before re-combining with the Stokes pulses. The transmitted pulses were coupled into a photonic crystal fiber (NL-1.4-775-945, Crystal Fibre, Denmark) to generate a broadband emission. A bandpass filter was used to select the near infra-red portion of the broadband emission for use as the Stokes pulses necessary for generating the CARS signal. The pump and Stokes pulses were combined and directed into the microscope assembly. Two scanning mirrors directed the laser pulses to the sample area of interest. The pulses were focused onto the sample through a 20x, 0.75 NA infinity-corrected air objective lens (Olympus, Japan) and the back scattered (epi-)signals were collected through the same objective lens. Collected light was coupled into a multi-mode fiber to allow for the acquisition of either spectra or images. For spectral acquisition the end of the fiber was connected to the same CCD-array based spectrometer used in the single photon set-up. The spectrometer collected spectra over a wavelength range covering that of the emitted TPEF and SHG signals but not the CARS signal. For image acquisition the proximal end of the fiber was connected to an array of PMTs (Hamamatsu, Japan), dichroic mirrors and color filters normally used for free-space microscopic imaging in the epi-detection configuration. Three PMTs simultaneously detected the TPEF, SHG, and CARS signals. Image acquisition and laser
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Atomic quantum memory for photon polarization

Atomic quantum memory for photon polarization

But looking beyond the lab, first and foremost, I would like to thank my parents for supporting me in every way throughout the last four years. This thesis represents my long journey through MIT, and as such I want to thank a number of people who have helped me in other projects and classes I have worked on throughout my four years here. Whether it was slogging through problem sets, performing analysis on the latest Junior Lab experiment, or heeding the call of Lobster Bisque during a blizzard, William McGehee, my old JLab partner, has been an incredible friend to me and I do not know if there is any way I will ever be able to repay him. Similarly, Ruth Shewmon and Elizabeth George, the other CUA UROPS, were an immeasurable source of strength in that our shared suffering always allowed me to continue working hard. The same goes for all of the other brilliant graduate students and UROPS at the CUA who helped me along the way, especially Marko Cetina, Andrew Grier, Ian Leroux, and Monika Schleier-Smith. And last but not least at the CUA, the amazing Ketterle coffee machine.
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Photon correlations on a room temperature semi-conductor single photon emitter.

Photon correlations on a room temperature semi-conductor single photon emitter.

Résumé Le travail proposé dans cette thèse est basé sur des expériences de corrélation de photons faites sur un émetteur de photons uniques semi conducteur: une boite quantique de CdSe dans un nanol de ZnSe. La première démonstration de production de photons uniques d'une boite quantique épitaxiée à température ambiante y est présentée. La transition biexcitonique est la source utilisée et son rapide taux d'émission spontanée (temps de vie radiatif de 300 ps) en fait un emetteur extremement rapide. Pour expliquer ce résultat, nous avons étudié expéri- mentalement et théoriquement l'ecacité de couplage exciton-phonon et ses conséquences sur l'intensité de l'exciton avec la température. Nous présentons également des résultats optiques portant sur la robustesse de cette structure à haute température. La technique de corrélation de photons est également appliquée sur des boites quantiques chargées. La présence du biex- citon chargé nous a permis de sonder la structure ne du trion excité, de décrire ses processus de relaxations et d'obtenir une mesure directe du temps de spin ip du trou sur l'état p. Des indications sont également données sur la nature possible du dopage. Nous avons aussi étudié la diusion spectrale de l'émetteur causée par les uctuations électroniques de son environnement. Par un travail théorique nous montrons comment interpréter l'eet de l'élargissement phonon de la raie homogène, (processus Poissonien) combiné avec l'eet de la diusion spectral (processus Markovien) sur la fonction d' autocorrélation de la demi-raie. Grace à l'expérience, nous conclu- ons sur la statistique de l'énergie d'émission de l'émetteur à haute température. Nous appliquons cette théorie sur les nanols et interprétons les dépendances en température et en puissance des uctuations de l'environnement grace au modèle de Kubo-Anderson.
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Tantalum STJ for Photon Counting Detectors

Tantalum STJ for Photon Counting Detectors

IV. S INGLE PHOTON DETECTION The same Ta-based junction has been used for optical photon counting at a temperature of 0.15K. The light source is a pulsed photodiode emitting in the near infrared (=0.78 µm). This is an ABB Hafo 1A330 device with an output power of 100 µW and a rise/fall time of 15 ns. The photodiode is placed inside the cryostat and is pulsed with an electrical signal of a few microseconds sent from the outside. The photodiode is coupled to a single mode optical fiber having a 5 m diameter core through a commercial SMA connector. This fiber is then fixed to the cold finger where the junction is placed, illuminating the back-side of the junction. Since the optical fiber tip is placed one centimeter away from the junction and the optical fiber diameter is very small, the coupling efficiency of the photodiode light to the junction is intentionally low in order to reduce the photon flux. This experimental set-up allows us to illuminate the junction with very few photons at each photodiode pulse by dilution of the optical fiber output beam. In addition, classical digital filtering methods are used to compute the photon counting data in order to minimize the effects of noise.
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Anomalous photon diffusion in atomic vapors

Anomalous photon diffusion in atomic vapors

with α = 2.41 ± 0.12. Although the obtained distribution has clearly a di- verging second moment, this measurement alone does not prove that light transport in the multiple scattering regime is superdiffusive, because the spectrum of light scattered in the first cell, and hence the jump size distribution for the first step, depends on the laser frequency. The fre- quency redistribution is only partial [15]. To characterize the multiple scattering regime, we need to measure the jump size distribution function after several steps, once photons have lost memory of the initial laser frequency, so that the emission spectra has converged towards a limit spectra (see section 3 for a numerical demonstration of this convergence). To achieve this, we use a three cell con- figuration (Fig. 1(d)). Laser photons are sent in a first rubidium cell of high atomic density, where they are scat- tered several times (∼ 4), before reaching a second source cell, where they undergo one more scattering event with a well-known position before being sent to the observation cell. We thus measure the jump size distribution func- tion in the multiple scattering regime. Once again, we find a power law asymptotic behavior P (x) ∼ 1/x α , with
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