Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 24 for “"SPDC"”.
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Specialist palliative day care : patients' perspectives
… psychosocial experiences of attendance at SPDC. Twelve studies were included. Evidence showed that patients value a person-centred approach which reduces isolation, increases social support, encourages communication and provides activities. Future research could focus on investigating why …
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Ultrafast sources of entangled photons for quantum information processing
… pairs is spontaneous parametric downconversion (SPDC) which finds its use in many QIP applications such as quantum key distribution (QKD) and linear optics quantum computation. SPDC is often used with ultrafast lasers to generate photon pairs with precise timing and engineered spectral …
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Generation of fiber-coupled, nondegenerate, polarization-entangled photons for quantum communication
… from spontaneous parametric downconversion (SPDC) enables many applications of quantum information processing. In this thesis, we use type-0 phase-matched downconversion of pump photons from a 532 nm continuous-wave laser to generate 798 nm signal and 1.6 tim idler photon pairs in …
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Phase-sensitive light : coherence theory and applications to optical imaging
Spontaneous parametric downconversion (SPDC) can produce pairs of entangled photons, i.e., a stream of biphotons. SPDC has been utilized in a number of optical imaging applications, such as optical coherence tomography, ghost imaging, holography and lithography, to obtain performance that cannot be …
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Target detection through quantum illumination
… Type-O spontaneous parametric downconversion (SPDC). The signal is attenuated and combined with large levels of noise. The signal is phase modulated to improve the observation by shifting it from DC to 16 kHz. The return signal and idler are recombined in an optical parametric amplifier (OPA) …
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Entangled optical state creation and characterization
… Spontaneous Parametric Down Conversion (SPDC) crystal setup and characterize the quality of the source as a function of state fidelity and strength of Bell's inequality violation. Experimental results show a Bell statistic of 2.23 with a fidelity of 0.745 with the theoretical φ+ Bell …
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Generation and characterization of spectrally factorable biphotons
… pulsed spontaneous parametric down-conversion (SPDC) in a custom-fabricated periodically-poled KTiOPO₄ (PPKTP) crystal under extended Gaussian phase-matching conditions. The high purity achieved is made possible by the Gaussian phase-matching function of our custom PPKTP crystal. Without …
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High performance photon-pair source based on a fiber-coupled periodically poled KTiOPO₄ waveguide
… based on spontaneous parametric downconversion (SPDC) in a nonlinear crystal waveguide have been shown to be significantly more efficient than those in a bulk crystal. To utilize waveguide sources in quantum information processing (QIP) applications, it is highly desirable to integrate additional …
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Tools for quantum optics : pulsed polarization-maintaining Er-doped fiber laser and spatial mode manipulation in spontaneous parametric downconversion
… from spontaneous parametric downconversion (SPDC) into single-mode optical fibers, which are useful for transporting entangled photons. Using a setup with a tunable 532 nm pump waist in a nonlinear crystal, we achieved an effective coupling efficiency of 48.8% of the 797 nm signal light into …
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Optical nonlinear effects and photon pair production in modulated materials
… for spontaneous parametric down-conversion (SPDC) i.e. amplification of vacuum fluctuations mediated by optical nonlinearity. We present a model of SPDC in MoS2 monolayers and show that our data are compatible with theoretical estimates. We show exciting indications that SPDC may be possible …
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High-dimensional entanglement-based quantum key distribution
… (CW) spontaneous parametric downconversion (SPDC). This thesis focuses on the implementation of a time-energy entanglement-based QKD system, with the development of several enabling technologies including an efficient single-spatial-mode source of time-energy entangled photons based on a …
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Quantum nonlinear optics: applications to quantum metrology, imaging, and information
… of spontaneous parametric down conversion (SPDC). This process is mediated by the second order nonlinear susceptibility of the material. When pumped in a high gain regime, these crystals give rise to optical parametric amplification, which is a viable source of squeezed light. The vast …
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Pure sources and efficient detectors for optical quantum information processing
… of spontaneous parameteric downconversion (SPDC) sources of photon pairs, and in doing so, produce such an optimized source. We report an SPDC source which produces pure heralded single photons with little or no spectral filtering, allowing a significant rate enhancement. Our work on …
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Media agenda-building battles between Greenpeace and Shell : a rhetorical and discursive approach
… the Shell Petroleum Development Corporation (SPDC) (hereafter referred to as Shell-Nigeria), and Greenpeace (amongst others) over environmental pollution in Ogoniland, Nigeria.These two battles were chosen mainly because they share the same main protagonists - Greenpeace and Shell - providing …
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Growth, characterization and implementation of semiconductor sources of highly entangled photons
… spontaneous parametric down-conversion (SPDC). Unfortunately, their susceptibility to perturbations from the solid-state environment significantly affects the photon coherence and entanglement degree. Furthermore, most quantum dot types suffer from poor wavelength control and emitter …
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Applications of single-photon two-qubit quantum logic to the quantum information science
… spontaneous parametric down conversion (SPDC) process within a bidirectionally pumped periodically-poled potassium titanyl phosphate (PPKTP) crystal embedded in a polarization Sagnac interferometer and generation of hyper-entangled photon pairs that are simultaneously entangled in the …
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Generation, manipulation and detection of NIR and MIR entangled photon pairs
… goal to generate MIR entangled photon pairs via SPDC. Alongside, the generation and manipulation of correlated photon pair sources by means of spontaneous FWM in traditional silicon waveguides and microring resonators at telecom wavelength was also investigated. For the detection of MIR photon …
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High-dimensional Quantum Key Distribution with Frequency Encoding
… in the spontaneous parametric down-conversion (SPDC) process through custom engineering of phase-matching conditions. The heralded single-photon source is useful in measurement-based quantum applications, where indistinguishable single photons are required to ensure high-visibility photon-photon …
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Ultrabright source of polarization-entangled photons from cavity-enhanced downconversion
… This novel source is more suitable than previous SPDC sources for transferring entanglement to future qubit storage such as a trapped rubidium memory. The narrow bandwidth is imposed by modifying the spectrum of the photon pairs by performing the down-conversion inside a cavity. The collinear …
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High resolution measurement of telecommunication component polarization mode dispersion by means of quantum interferometry
… type-II Spontaneous Parametric Down Conversion (SPDC). Our result paves the way for building future test and measurement devices that will be capable of resolving even smaller PMD values in discrete components of future optical communication systems, ultimately with atto-second resolution.
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