- 标题
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High Quality Entangled Photon Pair Generation in Periodically Poled Thin-Film Lithium Niobate Waveguides
摘要： A thin-film periodically poled lithium niobate waveguide was designed and fabricated which generates entangled photon pairs at telecommunications wavelengths with high coincidences-to-accidentals counts ratio CAR > 67000, two-photon interference visibility V > 99%, and heralded single-photon autocorrelation g(0) < 0.025. Nondestructive in situ diagnostics were used to determine the poling quality in 3D. Megahertz rates of photon pairs were generated by less than a milliwatt of pump power, simplifying the pump requirements and dissipation compared to traditional spontaneous parametric down-conversion lithium niobate devices.
关键词： lithium niobate waveguides,quantum information processing,entangled photon pairs,telecommunications wavelengths
更新于2025-09-23 15:19:57
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All-photonic quantum teleportation using on-demand solid-state quantum emitters
摘要： All-optical quantum teleportation lies at the heart of quantum communication science and technology. This quantum phenomenon is built up around the nonlocal properties of entangled states of light that, in the perspective of real-life applications, should be encoded on photon pairs generated on demand. Despite recent advances, however, the exploitation of deterministic quantum light sources in push-button quantum teleportation schemes remains a major open challenge. Here, we perform an important step toward this goal and show that photon pairs generated on demand by a GaAs quantum dot can be used to implement a teleportation protocol whose fidelity violates the classical limit (by more than 5 SDs) for arbitrary input states. Moreover, we develop a theoretical framework that matches the experimental observations and that defines the degree of entanglement and indistinguishability needed to overcome the classical limit independently of the input state. Our results emphasize that on-demand solid-state quantum emitters are one of the most promising candidates to realize deterministic quantum teleportation in practical quantum networks.
关键词： GaAs quantum dot,entangled photon pairs,quantum emitters,quantum teleportation,quantum communication
更新于2025-09-23 15:19:57
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Highly uniform and symmetric epitaxial InAs quantum dots embedded inside Indium droplet etched nanoholes
摘要： III?V semiconductor quantum dots (QDs) obtained by local droplet etching technology provide a material platform for generation of non-classic light. However, using this technique to fabricate single emitters for a broad spectral range remains a signi?cant challenge. Herein, we successfully extend the QD emission wavelength to 850–880 nm via highly uniform and symmetric InAs QDs located inside indium-droplet-etching nanoholes. The evolution of InGaAs nanostructures by high temperature indium droplet epitaxy on GaAs substrate is revealed. By carefully designing the appropriate growth conditions, symmetric QDs with the a small ?ne structure splitting of only ～4.4?±?0.8 μeV are demonstrated. Averaging over the emission energies of 32 QDs, an ensemble broadening of 12 meV is observed. Individual QDs are shown to emit nonclassically with clear evidence of photon antibunching. These highly uniform and symmetric nanostructures represent a very promising novel strategy for quantum information applications.
关键词： entangled photon pairs,symmetric quantum dots,droplet etched nanoholes,molecular beam epitaxy
更新于2025-09-19 17:13:59
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Time-Energy Entangled Photon Pairs from Doppler-Broadened Atomic Ensemble Via Collective Two-Photon Coherence
摘要： We experimentally demonstrate two-photon interference between a time-energy entangled photon pair generated from Doppler-broadened cascade-type 87Rb atoms using an unbalanced Michelson interferometer. In our system, the CW-mode time-energy entangled photon-pair sources are generated via the SFWM process and the collective two-photon coherence effect of a Doppler-broadened cascade-type atomic ensemble. The coherence time of the two-photon state from the Doppler-broadened atomic ensemble is more than 100 times longer than that of the single-photon state. We investigate two-photon interference (TPI) by means of highly time-resolved coincidence detection and determine the two-photon coherence length of a photon pair from the Doppler-broadened atomic ensemble. We observed fourth-order interference with visibility as high as 97% with the time-energy entangled CW-mode photon pairs from the atomic ensemble for the first time.
关键词： Doppler-Broadened Atomic Ensemble,Quantum Optics,Time-Energy Entangled Photon Pairs,Collective Two-Photon Coherence,Two-Photon Interference
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Conversion of two Photons with Different Color by a Single Waveguide for Quantum Networks
摘要： Quantum communication would enable opportunities such as secure communication. A quantum network with quantum nodes and quantum channels is necessary for this. The realization of such a quantum network requires the ability to process, store and send photons over long distances. It is not very likely that a single physical system can accomplish all these operations. Therefore, dissimilar quantum systems have to be connected in future quantum networks. Quantum channels are likely to be based on the existing fiber network because it is already well established. The fiber network operates at telecom wavelength (1550 nm) since the losses in fibers are minimal at this wavelength. That is why quantum states at telecom wavelength are needed. Unfortunately, suitable single photon sources and quantum memories are not available at telecom wavelength. Frequency conversion provides the possibility to alter the wavelength of a single photon to another wavelength. With frequency conversion it is possible to convert the VIS/NIR single photon to telecom wavelength and transfer the state over long distances. However, quantum networks do not require single photons but rather entangled photon pairs. Quantum dots are able to generate entangled photon pairs via a biexciton cascade emission. The emitted photons of a cascaded emission usually have slightly different wavelengths. The frequency conversion of the entangled photon pair on a single device would be advantageous for building quantum nodes for real life applications. We present a frequency conversion based on a single lithium niobate waveguide with different local temperatures to convert two different wavelengths on the same chip. The setup consists of a 2100 nm pump laser and a fiber coupled input port for the two biexciton photons (894 nm and 892 nm). These three wavelengths are focused by a lens into a nonlinear crystal with two different local temperatures. Each segment converts one of the incoming wavelengths. The converted signal is coupled into an optical fiber and guided to a filter system, which removes remaining pump light and generated noise photons. A proof of principle experiment was performed with attenuated laser light, where the converted spectrum is shown.
关键词： lithium niobate waveguide,frequency conversion,Quantum communication,entangled photon pairs,quantum network
更新于2025-09-11 14:15:04