Single-photon Frequency Upconversion for Long-distance Quantum Teleportation and Communication PDF Download

Author: Marius A. Albotǎ
Publisher:
ISBN:
Category :
Languages : en
Pages : 139

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Entanglement generation, single-photon detection, and frequency translation that preserves the polarization quantum state of the photons are essential technologies for long distance quantum communication protocols. This thesis investigates the application of polarization entanglement to quantum communication, including frequency upconversion, photon-counting detection, and photon-pair and entanglement generation. We demonstrate a near-unity efficient frequency conversion scheme that allows fast and efficient photon counting at wavelengths in the low-loss fiber optic and atmospheric transmission band near 1.55 /im. This upconverter, which is polarization-selective, is useful for classical as well as quantum optical communication. We investigate several schemes that allow frequency translation of polarization-entangled photons generated via spontaneous parametric downconversion in second order non-linear crystals. We demonstrate upconversion from 1.56 to 0.633 m that preserves the polarization state of an arbitrarily polarized input. The polarization-insensitive upconverter uses bidirectional sum-frequency generation in bulk periodically poled lithium niobate and a Michelson interferometer to stabilize the phase. Using this bidirectional upconversion technique, entangled photons produced in a periodically poled parametric downconverter can be translated to a different wavelength with preservation of their polarization state. We discuss the implications of these results for quantum information processing.

Author: Jason Scott Pelc
Publisher:
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Category :
Languages : en
Pages :

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The ability to manipulate the carrier frequency of quantum states of light, through a process called quantum frequency conversion (QFC), has numerous applications for both technology and basic science. For example, one can upconvert a single-photon-level signal in the 1.5-micron telecommunications band (where single-photon detection has been challenging) to a visible wavelength to take advantage of well-developed single-photon detectors based on silicon avalanche photodiodes. On the more fundamental side, the manipulation of a single photon's frequency may enable the construction of networks of dissimilar quantum systems, whereby one can imagine generating many-body entangled quantum states over vast distances. Quantum frequency conversion will only be useful if it can be done both efficiently and with little added noise. We demonstrated a conversion efficiency exceeding 99.99% using reverse-proton-exchange waveguides in periodically poled lithium niobate with approximately 150 mW of pump power. Noise has been a more serious issue: the generation of noise photons, due to inelastic scattering of light from the strong pump laser used to drive the frequency conversion, has limited the utility of QFC devices in many applications. We present an analysis of the two primary noise processes in QFC devices (spontaneous Raman scattering and spontaneous parametric fluorescence), and offer solutions on how they may be either mitigated or avoided completely. We then discuss applications of QFC devices for up- and downconversion of single-photon signals. We used a long-wavelength pump to enable high-efficiency and low-noise single-photon detection for 1550-nm telecom band signals, and demonstrated a cascaded frequency conversion approach that enabled low timing jitter as well. We also demonstrated a downconversion quantum interface, in which the emission from a single semiconductor quantum dot at a wavelength of 910 nm was downconverted to 1560 nm while maintaining the single-photon character of the light. The results presented in this dissertation indicate a promising future for QFC devices as the field of quantum communications matures.

Author: Nicolas Maring
Publisher:
ISBN:
Category :
Languages : en
Pages : 144

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The ability to control the optical frequency of quantum state carriers (i.e. photons) is an important functionality for future quantum networks. It allows all matter quantum systems - nodes of the network - to be compatible with the telecommunication C-band, therefore enabling long distance fiber quantum communication between them. It also allows dissimilar nodes to be connected with each other, thus resulting in heterogeneous networks that can take advantage of the different capabilities offered by the diversity of its constituents. Quantum memories are one of the building blocks of a quantum network, enabling the storage of quantum states of light and the entanglement distribution over long distances. In our group, two different types of memories are investigated: a cold atomic ensemble and an ion-doped crystal. In this thesis I investigate the quantum frequency conversion of narrow-band photons, emitted or absorbed by optical quantum memories, with two different objectives: the first one is to connect quantum memories emitting or absorbing visible single photons with the telecommunication wavelengths, where fiber transmission loss is minimum. The second and main goal is to study the compatibility between disparate quantum nodes, emitting or absorbing photons at different wavelengths. More precisely the objective is to achieve a quantum connection between the two optical memories studied using quantum frequency conversion techniques. The main core of this work is the quantum frequency conversion interface that bridges the gap between the cold ensemble of Rubidium atoms, emitting photons at 780nm, and the Praseodymium ion doped crystal, absorbing photons at 606nm. This interface is composed of two different frequency conversion devices, where a cascaded conversions takes place: the first one converts 780nm photons to the telecommunication C-band, and the second one converts them back to visible, at 606nm. This comes with several challenges such as conversion efficiency, phase stability and parasitic noise reduction, which are important considerations to show the conservation of quantum behaviors through the conversion process. This work can be divided in three parts. In a first one, we built a quantum frequency conversion interface between 606nm and the C-band wavelength, capable of both up and down-conversion of single photon level light. We also characterized the noise processes involved in this specific conversion. In the down-conversion case we showed that memory compatible heralded single photons emitted from a photon pair source preserve their non-classical properties through the conversion process. In the up-conversion case, we showed the storage of converted telecom photons in the praseodymium doped crystal, and their retrieval with high signal to noise ratio. The second part of the work was devoted to the conversion of photons from an emissive Rubidium atomic quantum memory to the telecom C band. In this work we converted the heralding photons from the atomic ensemble and measured non-classical correlations between a stored excitation and a C-band photon, necessary for quantum repeater applications. In the last part of the thesis, we setup the full frequency conversion interface and showed that heralded photons emitted by the atomic ensemble are converted, stored in the solid state memory and retrieved with high signal to noise ratio. We demonstrated that a single collective excitation stored in the atomic ensemble is transfered to the crystal by mean of a single photon at telecom wavelength. We also showed time-bin qubit transfer between the two quantum memories. This work represents the first proof of principle of a photonic quantum connection between disparate quantum memory nodes. The results presented in this thesis pave the way towards the realization of modular and hybrid quantum networks.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 17

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In this project, we have carried out the pioneering work for long-distance quantum communication using atomic ensembles for photon-state storage and for implementation of quantum repeaters. This work was followed by many groups and is now considered as one of the most promising approaches to overcoming photon losses in long-distance quantum communication. Specific highlights include theoretical proposals for quantum repeaters based on atomic ensembles (Nature, 414, 413, 2001), atom-atom correlations mediated by dark-state polaritons (Phys. Rev. Lett., 88, 243602, 2002), generation of stationary pulses of light (Phys. Rev. Lett, 89, 143602, 2002); experimental demonstrations of atomic memory for correlated photon states (Science, 301, 196, 2003), stationary pulses of light (Nature 426, 638, 2003), shaping quantum pulses via atomic memory (Phys. Rev. Lett. 93, 233602, 2004)), and finally realization of two-node quantum network involving generation and storage of single photon pulses in two remote ensembles (Nature, 438, 837, 2005). Finally, we proposed and analyzed a novel method that uses fixed, minimal physical resources to achieve generation and nested purification of quantum entanglement for quantum communication over arbitrarily long distances. In this method, solid-state single photon emitters with two internal degrees of freedom formed by an electron spin and a nuclear spin are used to build intermediate nodes in a quantum channel (Phys. Rev. Lett. 96,070504, 2006). Recently, we have experimentally demonstrated such a node using Nitrogen-Vacancy centers in room temperature diamond lattice (submitted to Science, 2007).

Author: Keyu Xia
Publisher: BoD – Books on Demand
ISBN: 183880353X
Category : Technology & Engineering
Languages : en
Pages : 112

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Book Description
This short book aims to present basic information about single photons in a quick read but with not many details. For this purpose, it only introduces the basic concept of single photons, the most important method of generating single photons in experiments, and a specific emerging field.

Author: Robert Hadfield
Publisher: Springer
ISBN: 3319240919
Category : Computers
Languages : en
Pages : 256

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Book Description
This book presents the basics and applications of superconducting devices in quantum optics. Over the past decade, superconducting devices have risen to prominence in the arena of quantum optics and quantum information processing. Superconducting detectors provide unparalleled performance for the detection of infrared photons in quantum cryptography, enable fundamental advances in quantum optics, and provide a direct route to on-chip optical quantum information processing. Superconducting circuits based on Josephson junctions provide a blueprint for scalable quantum information processing as well as opening up a new regime for quantum optics at microwave wavelengths. The new field of quantum acoustics allows the state of a superconducting qubit to be transmitted as a phonon excitation. This volume, edited by two leading researchers, provides a timely compilation of contributions from top groups worldwide across this dynamic field, anticipating future advances in this domain.

Author: Mohsen Razavi
Publisher:
ISBN:
Category :
Languages : en
Pages : 138

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(Cont.) We propose a non-adiabatic mechanism for driving off-resonant Raman transitions that can be used in loading trapped-atom quantum memories. Our method is more flexible than its adiabatic counterpart in that it allows use of larger cavities and a larger class of driving sources. We also describe two proposed implementations for long-distance quantum communication-one that uses trapped atoms as quantum memories and another that employs atomic ensembles for quantum storage. We provide, for the first time, a detailed quantitative performance analysis of the latter system, which enables us to compare these two systems in terms of the fidelity and the throughput that they achieve for entanglement distribution, repeater operation, and quantum teleportation. Finally, we study quantum computing systems that use the cross-Kerr nonlinearity between single-photon qubits and a coherent mode of light. The coherent beam serves a mediating role in coupling two weak single-photon beams. We analytically study this structure using a continuous-time formalism for the cross-Kerr effect in optical fibers. Our results establish stringent conditions that must be fulfilled for the system's proper operation.

Author:
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Category : Dissertations, Academic
Languages : en
Pages : 924

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Author: Michael Kobierski
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Entanglement is a rare resource only a select few people worldwide can create. Its fundamentally non-classical behavior seeds a tree of ideas from which transformative technologies in information processing, communication, and imaging grow. Particularly interesting is entanglement between photons in a pair made by a quantum dot, the most competitive contender among quantum photonic devices. A strength of semiconductor quantum dots is their deterministic reliability and potential for production at scale. The associated price is anchored in their inherent flaw: sensitivity to imperfections in their shape puts the entanglement they generate in motion. Thus, unless a specific entangled photon pair is caught at just the right moment, it will appear as though it is in fact not entangled at all. Ingenious methods for making quantum dots perfect again have been devised,almost exclusively built around reshaping the dot by physical, electric, or magnetic means. One completely different proposal stands out, which instead stops the entanglement's motion once it has already been created. As a purely optical technique it can be used for any quantum dot and is completely non-intrusive. This is the method of the rotating half-wave plate. The entanglement between photons in a pair revolves up to a few billion times per second and halting it requires a correction one-half that rate. Physically spinning a crystal waveplate at that tremendous speed is impossible, but if the properties of a crystal are spun in an identical way such quickly varying entanglement can be restored to its starting point with ease. This is the principle of electro-optic modulation. This thesis shows the very first demonstration of slowing the frequency of single photons in a stream by using an electro-optical rotating half-wave plate prototype. Initial results show a reduction in frequency by 127.75 million oscillations per second. Any quantum dot whose entanglement precesses no more quickly than 255.5 MHz can thus directly make use of the technique contained herein.

Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 11

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Quantum repeaters create long-distance entanglement between quantum systems while overcoming difficulties such as the attenuation of single photons in a fiber. Recently, an implementation of a repeater protocol based on single qubits in atomic ensembles and linear optics has been proposed [Duan et al., Nature (London) 414, 413 (2001)]. Motivated by rapid experimental progress towards implementing that protocol, here we develop a more efficient scheme compatible with active purification of arbitrary errors. Using similar resources as the earlier protocol, our approach intrinsically purifies leakage out of the logical subspace and all errors within the logical subspace, leading to greatly improved performance in the presence of experimental inefficiencies. Our analysis indicates that our scheme could generate approximately one pair per 3 min over 1280 km distance with fidelity (F> or = 78%) sufficient to violate Bell's inequality.