True on-demand high-repetition-rate single-photon sources are highly sought after for quantum information processing applications. However, any coherently driven two-level system suffers from a finite re-excitation probability under pulsed excitation, causing undesirable multi-photon emission. Here, we present solid-state source of single photons yielding raw second-order coherence g(2)(0)=(7.5±1.6)×10−5 without background subtraction or data processing. To this date, is the lowest value...

Photonic quantum technologies call for scalable light sources that can be integrated, while providing the end user with single and entangled photons on demand. One promising candidate is strain free GaAs/AlGaAs dots obtained by aluminum droplet etching. Such exhibit ultra low multi-photon probability an unprecedented degree of photon pair entanglement. However, different to commonly studied InGaAs/GaAs Stranski-Krastanow mode, a near-unity indistinguishability from these emitters have proven...

Entangled photons are an integral part in quantum optics experiments and a key resource imaging, communication, photonic information processing. Making this available on-demand has been ongoing scientific challenge with enormous progress recent years. Of particular interest is the potential to transmit over long distances, making only reliable flying qubit. at telecom C-band could be directly launched into single-mode optical fibers, enabling worldwide communication via existing...

The tailoring of the physical properties semiconductor nanomaterials by strain has been gaining increasing attention over last years for a wide range applications such as electronics, optoelectronics and photonics. ability to introduce deliberate fields with controlled magnitude in reversible manner is essential fundamental studies novel materials may lead realization advanced multi-functional devices. A prominent approach consists integration active nanomaterials, thin epitaxial films or...

Semiconductor quantum dots are crucial parts of the photonic technology toolbox because they show excellent single-photon emission properties in addition to their potential as solid-state qubits. Recently, there has been an increasing effort deterministically integrate single semiconductor into complex circuits. Despite rapid progress field, it remains challenging manipulate optical waveguide-integrated emitters a deterministic, reversible, and nonintrusive manner. Here we demonstrate new...

We investigate the degree of indistinguishability cascaded photons emitted from a 3-level quantum ladder system; in our case biexciton-exciton cascade semiconductor dots. For system we theoretically demonstrate that is inherently limited for both and determined by ratio lifetimes excited intermediate states. experimentally confirm this finding comparing interference visibility non-cascaded emission same dot. Quantum optical simulations produce very good agreement with measurements allow to...

The requirements in quantum optics experiments for high single-photon detection efficiency, low timing jitter, dark count rate and short dead time have been fulfilled with the development of superconducting nanowire detectors.Although they offer a efficiency above 90%, achieving resolution devices made amorphous materials is challenge, particularly at temperatures 0.8 K. Devices from niobium nitride titanium allow us to reach best jitter but, turn, stronger terms film quality achieve...

Rydberg excitons are, with their ultrastrong mutual interactions, giant optical nonlinearities, and very high sensitivity to external fields, promising for applications in quantum sensing nonlinear optics at the single-photon level. To design it is necessary know how other excited states relax lower-lying exciton states. Here, we present photoluminescence excitation spectroscopy as a method probe transition probabilities from various excitonic cuprous oxide, show $T=38$ mK principal numbers...

Integration of superconducting devices on photonic platforms opens up a wide range functionalities and applications. We report NbTiN thin films deposited SiO2, Si3N4, GaAs, LiNbO3, AlN as well monolayer hexagonal boron nitride, using universal reactive co-sputtering recipe. The morphology the properties with thickness 10 nm were characterized by atomic force microscopy electrical transport measurements. Superconducting strip photon detectors fabricated design suitable for waveguide...

Resonance fluorescence has played a major role in quantum optics with predictions and later experimental confirmation of nonclassical features its emitted light such as antibunching or squeezing. In the Rayleigh regime where most originates from scattering photons subnatural linewidth, would appear to coexist sharp spectral lines. Here, we demonstrate that this simultaneous observation linewidth is not possible simple resonant excitation. Using an epitaxial dot for two-level system,...

Entangled photon generation at 1550 nm in the telecom C-band is of critical importance as it enables realization quantum communication protocols over long distance using deployed telecommunication infrastructure. InAs epitaxial dots have recently enabled on-demand entangled photons this wavelength range. However, time-dependent state evolution, caused by fine-structure splitting, currently limits fidelity to a specific state. Here, we show suppression for micromachined piezoelectric...

We demonstrate the first wavelength-tunable electrically pumped source of nonclassical light that can emit photons with wavelength in resonance D2 transitions 87Rb atoms. The device is fabricated by integrating a novel GaAs single-quantum-dot light-emitting diode (LED) onto piezoelectric actuator. By feeding emitted into 75 mm long cell containing warm vapor, we observe slow-light temporal delay up to 3.4 ns. In view possibility using atomic vapors as quantum memories, this work makes an...

The implementation of fiber-based long-range quantum communication requires tunable sources single photons at the telecom C-band. Stable and easy-to-implement wavelength-tunability individual is crucial to (i) bring remote into resonance, (ii) define a wavelength standard, (iii) ensure scalability operate repeater. So far, most promising for true, are semiconductor dots, due their ability deterministically reliably emit entangled photons. However, required hard attain. Here, we show stable...

Strain engineering allows the physical properties of materials and devices to be widely tailored, as paradigmatically demonstrated by strained transistors semiconductor lasers employed in consumer electronics. For this reason, its potential impact on our society has been compared that chemical alloying. Although significant progress made last years nanomaterials, strain fields (which are tensorial nature, with six independent components) still mostly used a "scalar" and/or static fashion....

Quantum communication networks will connect future generations of quantum processors, enable metrological applications, and provide security through key distribution. We present a testbed that is part the municipal fiber network in greater Stockholm metropolitan area for resource distribution 20 km long based on semiconductor dots emitting telecom C-band. utilize service to generate random numbers passing NIST test suite SP800-22 at subscriber 8 outside city with bit rate 23.4 kbit/s.

Lithium niobate, because of its nonlinear and electro-optical properties, is one the materials choice for photonic applications. The development nanostructuring capabilities thin film lithium niobate (TFLN) permits fabrication small footprint, low-loss optical circuits. With recent implementation on-chip single-photon detectors, this architecture among most promising realizing quantum optics experiments. In Letter, we report on superconducting nanowire detectors (SNSPDs) based NbTiN 300 nm...

Long-range quantum communication requires the development of in-out light-matter interfaces to achieve a advantage in entanglement distribution. Ideally, these interconnections should be as fast possible high-rate entangled qubits Here, we demonstrate coherent quanta exchange between single photons generated on-demand from GaAs dot and atomic ensemble $^{87}$Rb vapor memory. Through an open system analysis, mapping quantized electric field coherence ensemble. Our results play pivotal role...

On-demand sources of entangled photons for the transmission quantum information in telecom C-band are required to realize fiber-based networks. So far, non-deterministic states light were used long distance entanglement distribution this lowest loss wavelength range. However, they fundamentally limited either efficiency or security due their Poissonian emission statistics. Here, we show on-demand generation photon pairs by an InAs/GaAs semiconductor dot. Using a robust phonon-assisted...

We develop a structure to efficiently extract photons emitted by GaAs quantum dot tuned rubidium. For this, we employ broadband microcavity with curved gold backside mirror that fabricate combination of photoresist reflow, dry reactive ion etching in an inductively coupled plasma, and selective wet chemical etching. Precise reflow control allows us achieve parabolic short focal distance 265 nm. The fabricated structures yield predicted (measured) collection efficiency 63% (12%), improvement...

In this paper, strain transfer efficiencies from a single crystalline piezoelectric lead magnesium niobate-lead titanate substrate to GaAs semiconductor membrane bonded on top are investigated using state-of-the-art x-ray diffraction (XRD) techniques and finite-element-method (FEM) simulations. Two different bonding studied, namely, gold-thermo-compression polymer-based SU8 bonding. Our results show much higher strain-transfer for the “soft” in comparison “hard” via gold-thermo-compression....

We investigate the indistinguishability of single photons generated from strain-free GaAs/AlGaAs quantum dots using pulsed resonance fluorescence techniques. In two-photon interference measurements we observe a photon with raw visibility 95%. This can be traced back to short intrinsic lifetime excitons and trions confined in GaAs demonstrates that for this material system generation is possible near-unity even without Purcell enhancement.

Fiber-based quantum networks require on-demand sources of entangled photons in the telecom C-band for long distance information transfer. Historically, field in-fiber entanglement distribution has been dominated by provided via spontaneous processes. In recent years, semiconductor dots have emerged as strong competitors terms generating single and due to their promise deterministic qubit generation NIR wavelength region. Here, we show polarization based on InAs/GaAs grown metal-organic...

We have studied the effects of optical-frequency light on proximitized InAs/Al Josephson junctions based highly n-doped InAs nanowires at varying incident photon flux and three different wavelengths. The experimentally obtained IV curves were modeled using a resistively shunted junction model which takes scattering contact interfaces into account. Despite fact that weak link is photosensitive, found to be surprisingly robust, interacting with radiation only through heating, whereas above...