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 36 for “"Downconversion"”.
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Advanced Downconversion Mixers for CMOS Radio Frequency Integrated Circuits
This thesis explores the design of advanced downconversion mixers in CMOS RF integrated circuits. First, a novel switched transconductor mixer with low power, low noise, and ultra-wide bandwidth is proposed. The transconductor stage with fixed DC operating point is switched by the ac-coupled local …
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Ultrabright source of polarization-entangled photons from cavity-enhanced downconversion
… down-conversion inside a cavity. The collinear downconversion geometry inside the linear cavity is achieved by using a quasi-phased-matched periodically-poled potassium titanyl phosphate (PPKTP) crystal. The single-pass free-space photon-pairs produced were demonstrated to be …
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Exploring possibilities to enhance silicon solar cell efficiency by downconversion of sunlight.
Improving the efficiency of solar cells is an active area of research in photovoltaic industry. The research work presented in this dissertation is based on a quest for better and improved silicon solar cells. The current work aims to explore different possibilities by studying advance approaches …
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Comparison, optimization, and application of various spontaneous parametric downconversion sources of polarization-entangled photon pairs
As benchtop quantum information protocols become increasingly more advanced and the distances over which these experiments are performed become significantly longer, integrated optics provide a small, robust, and practical alternative to traditional bulk optics. Waveguide technology makes it …
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Tools for quantum optics : pulsed polarization-maintaining Er-doped fiber laser and spatial mode manipulation in spontaneous parametric downconversion
… of light generated 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 …
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Applications of optical parametric downconversion : I. Self-phase locking, [and] II. Generation of entangled photon pairs in periodically-poled lithium niobate
Nonlinear optics plays a key role in many applications not only as a means of frequency synthesis and control, but also as a source of twin photons and other nonclassical states of light. Advances in nonlinear materials, including engineered nonlinear interactions through the use of quasi-phase …
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Generation of fiber-coupled, nondegenerate, polarization-entangled photons for quantum communication
… photon pairs 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 …
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One- and two-photon states for quantum information
Using correlated photons from parametric downconversion, we extend the boundaries of experimentally explored one- and two-qubit Hilbert space. These states are used to explore a variety of topics in quantum information. Specifically, we have created and characterized arbitrary single-qubit states …
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Investigations of quantum sensing techniques for deflection and displacement metrology
… correlations emerge from spontaneous parametric downconversion and how we utilize those correlations to improve the achievable resolution of a beam displacement. Finally, we discuss a possible way to use a quantum eraser to improve the signal from an atomic force microscope.
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A 60 Ghz Mmic 4x Subharmonic Mixer
… topologies are available that are capable of downconversion from 60 GHz. However, local oscillators (LOs) capable of providing adequate output power at mm-wave frequencies remain bulky and expensive. There are several techniques that allow the use of a lower frequency microwave LO to achieve …
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Design and Characterization of RFIC Voltage Controlled Oscillators in Silicon Germanium HBT and Submicron MOS Technologies
… VCOs are important components in the up or downconversion of RF signals in wireless transceivers. VCOs must have very low phase noise and spurious emissions, and be extremely power efficient to meet system requirements. To meet these specifications, VCOs require high-quality factor (Q) tank …
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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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Stream Communication and Computation in the Eight-meter-wavelength Transient Array (ETA) Radio Telescope
… The processing includes digital sampling, downconversion, filtering, Fast Fourier Transforms, and beamforming operations and is performed by 28 commercial-off-the-shelf (COTS) FPGA boards. Sixteen of the FPGA boards constitute the reconfigurable computing cluster (RCC) which performs the …
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Single-photon frequency upconversion for long-distance quantum teleportation and communication
… 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 …
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Target detection through quantum illumination
… created through 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 …
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A broadband Microwave Transceiver Front-end for an Airborne Software Defined Radio Experiment
… receiver requirements could be met by a single downconversion with high order filters and passband sampling. A series of analyses determined the requirements of the individual components that make up the system. Performance was verified by simulations using measured data of the individual …
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High performance photon-pair source based on a fiber-coupled periodically poled KTiOPO₄ waveguide
… sources 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 …
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Testing the limits of human vision with quantum states of light
… source based on spontaneous parametric downconversion and techniques from quantum optics. We review the existing evidence on single-photon vision, and show why no previous experiments with classical light sources (or otherwise) have truly been able to test it. We describe the heralded …
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Assessing materials quality for high efficiency electricity generation
… can reduce thermalization losses through the downconversion process of using a high energy photon to generate two lower energy electron-hole pairs. This occurs through the singlet-triplet fission process that excitons can undertake in tetracene. The effect of the interface quality between …
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Ultrafast sources of entangled photons for quantum information processing
… entangled photon 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 …
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