Entanglement is the hallmark of quantum mechanics. Quantum entanglement -- putting two or more identical particles into a non-factorable state -- has been leveraged for applications ranging from quantum computation and encryption to high-precision metrology. Entanglement is a practical engineering resource and a tool for sidestepping certain limitations of classical measurement and communication. Engineered nonlinear optical waveguides are an enabling technology for generating entangled photon pairs and manipulating the state of single photons. This dissertation reports on: i) frequency conversion of single photons from the mid-infrared to 843nm as a tool for incorporating quantum memories in quantum networks, ii) the design, fabrication, and test of a prototype broadband source of polarization and frequency entangled photons; and iii) a roadmap for further investigations of this source, including applications in quantum interferometry and high-precision optical metrology. The devices presented herein are quasi-phase-matched lithium niobate waveguides. Lithium niobate is a second-order nonlinear optical material and can mediate optical energy conversion to different wavelengths. This nonlinear effect is the basis of both quantum frequency conversion and entangled photon generation, and is enhanced by i) confining light in waveguides to increase conversion efficiency, and ii) quasi-phase matching, a technique for engineering the second-order nonlinear response by locally altering the direction of a material's polarization vector. Waveguides are formed by diffusing titanium into a lithium niobate wafer. Quasi-phase matching is achieved by electric field poling, with multiple stages of process development and optimization to fabricate the delicate structures necessary for broadband entangled photon generation. The results presented herein update and optimize past fabrication techniques, demonstrate novel optical devices, and propose future avenues for device development. Quantum frequency conversion from 1848nm to 843nm is demonstrated for the first time, with >75% single-photon conversion efficiency. A new electric field poling methodology is presented, combining elements from multiple historical techniques with a new fast-feedback control system. This poling technique is used to fabricate the first chirped-and-apodized Type-II quasi-phase-matched structures in titanium-diffused lithium niobate waveguides, culminating in a measured phasematching spectrum that is predominantly Gaussian (R^2 = 0.80), nearly eight times broader than the unchirped spectrum, and agrees well with simulations.

Dichoptic presentation of vernier stimuli, i.e., one segment to each eye, yielded three times higher thresholds than binocular presentation, mainly due to uncorrelated movements of both eyes. Thresholds allow one to calculate an upper estimate for the amplitudes of uncorrelated eye movements during fixation. This estimate matches the best results from direct eye position recording, with the calculated mean amplitude of eye tremor corresponding to roughly one photoreceptor diameter. The combined amplitude of both correlated and uncorrelated eye movements was also measured by delaying one segment of the vernier relative to its partner under monocular or dichoptic conditions.

The thesis "Experimental physics education at secondary school using the Pasco system," deals with the support of digital technology in education and shows a new use of information systems at secondary schools. It is focused on the use of a specialized set of measuring probes, sensors and other accessories in the experimental classes. It also focuses on the use of these devices in selected elementary schools in chosen subjects. The entire work will be written within the meaning of guide for physics teachers. It will include information about the products available on the Czech market, a set of experimental examples of various topics, including solutions, research relating to the use of experimental systems at schools and a research among pupils, whether these aids facilitate understanding of the topic. Part of the work will be filmed demonstration of experimental physics class, using a Pasco system.

The thesis "Physical measurements and health education" looks at physical quantities that are related to human health and can be measured in a elementary school environment. It focuses especially on the cross-curricular relationship between physics and health education and also on the use of relevant online measurement systems. As part of this thesis, we suggest a number of activities that exploit this relationship.

The diploma thesis describes selected Vernier sensors and demonstrates their utilization in schools. The selection of digital tools is focused on medial area. In particular, the thesis deals with the ECG, spirometer, and dynamometer sensors. In the theoretical part, the history of the Vernier company is presented and the Vernier system and its benefits are discussed with special regard to the workflow from preparation phase to the process of measuring which can be used in classrooms. The research part consists of individual measuring experiments utilizing the sensors and their comparison with medical tools.

In this project laser absorption spectroscopy was performed on a flame in a Fabry-Pérot cavity, using an optical frequency comb. Optical frequency comb spectroscopy is a technique that allows broadband ultra-sensitive detection of molecular species in gas phase. Optical frequency combs are generated by femtosecond mode-locked lasers, which generate short pulses and whose spectrum consists of a comb of sharp laser lines covering a broad spectral range. Doing spectroscopy with optical frequency combs can hence be compared to measurements with thousand of synchronised continuous wave lasers simultaneously, which enables broadband sensitive measurements in short acquisition times. A Vernier spectrometer uses the filtering ability of the cavity to allow sequential transmission of parts of the frequency comb spectrum. Its technical simplicity and robustness make it a good candidate for measuring in turbulent environments. The aim of the project was to implement continuous-filtering Vernier spectroscopy in a setup for measuring absorption spectra in air and in a flame. This was done by using an Er:fiber femtosecond laser emitting in the near-infrared wavelength range and a Fabry-Pérot cavity containing the flame. The cavity, which consists of two highly reflective mirrors, lets the light of the comb interact with the molecules in the flame for each of the many round-trips it perform; thus increasing the sensitivity to absorption. An active locking mechanism was implemented to stabilize the coupling of the optical frequency comb to the cavity. The locking allowed multiple measurements to be averaged which reduced noise. A galvanometer scanner was added to the system which was used to measure a broad part of the comb spectrum. Hot water absorption lines were detected in the swept comb spectrum and a candidate absorption peak for OH absorption was recorded. The spectrometer today has opportunities for improvements. A frequency calibration should be implemented which is essential for making estimates of reactant/product concentrations in combustion processes.

abstract: A Single Event Transient (SET) is a transient voltage pulse induced by an ionizing radiation particle striking a combinational logic node in a circuit. The probability of a storage element capturing the transient pulse depends on the width of the pulse. Measuring the rate of occurrence and the distribution of SET pulse widths is essential to understand the likelihood of soft errors and to develop cost-effective mitigation schemes. Existing research measures the pulse width of SETs in bulk Complementary Metal-Oxide-Semiconductor (CMOS) and Silicon On Insulator (SOI) technologies, but not on Fin Field-Effect Transistors (FinFETs). This thesis focuses on developing a test structure on the FinFET process to generate, propagate, and separate SETs and build a time-to-digital converter to measure the pulse width of SET. The proposed SET test structure statistically separates SETs generated at NMOS and PMOS based on the difference in restoring current. It consists of N-collection devices to collect events at NMOS and P-collection devices to collect events at PMOS. The events that occur in PMOS of the N-collection device and NMOS of the P-collection device are false events. The logic gates of the collection devices are skewed to perform pulse expansion so that a minimally sustained SET propagates without getting suppressed by the contamination delay. A symmetric tree structure with an S-R latch event detector localizes the location of the SET. The Cartesian coordinates-based pulse injection structure injects external pulses at specific nodes to perform instrumentation and calibrate the measurement. A thermometer-encoded chain (vernier chain) with mismatched delay paths measures the width of the SET. For low Linear Energy Transfer (LET) tests, the false events are entirely masked and do not propagate since the amount of charge that has to be deposited for successful event propagation is significantly high. In the case of high LET tests, the actual events and false events propagate, but they can be separated based on the SET location and the width of the output event. The vernier chain has a high measurement resolution of ~3.5ps, which aids in separating the events. / Dissertation/Thesis / Masters Thesis Electrical Engineering 2020

No / Vernier acuity depends on the integration of information from multiple photoreceptors. For this reason, vernier acuity thresholds ought to exhibit effects of stimulus size and contrast analogous to those that occur in area summation experiments. In this paper, we consider some area and contrast effects found in vernier acuity experiments, and explain them with a model of detection and discrimination which we call the Noisy Template model. The Noisy Template model assumes that psychophysical tasks are performed (or can be approximated) by cross-correlation of the stimulus with a decision template which is optimal for the task at hand. The Noisy Template model crucially adds the assumption that the template contains noise. This yields inefficiency in the decision process which increases with stimulus size and contrast. Predictions of the Noisy Template model are derived for the case of vernier acuity, and compared with existing experiments.

La communauté de la chimie atmosphérique souffre d'un manque de mesures rapides, fiables résolues spatialement et temporellement pour un large éventail de molécules réactives (radicaux tels que NO2, OH, BrO, IO, etc). En raison de leur forte réactivité, ces molécules contrôlent largement la durée de vie et la concentration de nombreuses espèces clés dans l'atmosphère, et peuvent avoir un impact important sur le climat. Les concentrations de ces radicaux sont extrêmement faibles (ppbv ou moins) et très variable dans le temps et dans l'espace, ce qui impose un véritable défi lors de la détection. Dans la première partie de cette thèse, un spectromètre UV robuste, compacte et transportable est développé, exploitant la technique ML-CEAS pour mesurer à des niveaux très faibles (pptv et même en dessous) des molécules réactives d'importance atmosphérique, en particulier, les radicaux d'oxyde d'halogènes, afin de répondre aux besoins émergents. La technique ML-CEAS est basée sur le couplage d'un laser femtoseconde à blocage de modes à une cavité optique de haute finesse, qui agit comme un piège à photons pour augmenter l'interaction entre la lumière et l'échantillon de gaz intracavité. Cela permet d'améliorer fortement la sensibilité d'absorption. La limite de détection obtenue pour le radical IO est de 20 ppqv pour un temps d'acquisition de 5 minutes, ce qui est un résultat impressionnant. Dans la deuxième partie de cette thèse, une nouvelle technique spectroscopique est développée appelée effet Vernier, qui est également basé sur l'interaction entre un laser femtoseconde à blocage de mode et une cavité optique de haute finesse. Cette technique fournit une sensibilité de détection similaire à la technique ML-CEAS, mais l'avantage est que le nombre des éléments spectraux est donné par la finesse de la cavité optique et donc peut atteindre plusieurs dizaines de milliers. De plus, cette configuration simplifie le montage expérimental par la suppression du spectrographe qui est remplacé par une simple photodiode. Le temps d'acquisition d'un spectre peut être aussi réduit à moins d' 1 ms. / The atmospheric chemistry community suffers a lack of fast, reliable and space resolved measurements for a wide set of reactive molecules (e.g. radicals such as OH, NO3, BrO, IO, etc). Due to their high reactivity, these molecules largely control the lifetime and concentration of numerous key atmospheric species, and may have an important impact on the climate. The concentrations of such radicals are extremely low (ppbv or less) and highly variable in time and space, which imposes a real challenge during the detection. In the first part of this thesis, a compact, robust and transportable UV spectrometer is developed, exploiting the Mode-Locked Cavity Enhanced Absorption Spectroscopy (ML-CEAS) technique to measure pptv and sub-pptv levels of atmospherically important reactive molecules, in particular, halogen oxide radicals, to respond to the emerging needs. The ML-CEAS technique is based on coupling a Mode-Locked femtosecond laser to a high finesse optical cavity, which acts as a photon trap to increase the interaction between the light and the intracavity gas sample, which highly enhances the absorption sensitivity. The detection limit obtained for the IO radical is 20 ppqv (part per quadrillion), which is an impressive result. In the second part of this thesis, a new spectroscopic technique is developed, called Vernier effect, which is also based on the interaction between a mode-locked femtosecond laser with a high finesse optical cavity. This technique provides detection sensitivity similar to that of ML-CEAS technique, but the advantage is that the number of the spectral elements is given by the cavity finesse, so it can reach ten thousands, as well as this technique has a simple setup, where the spectrograph is replaced by a photodiode. Additionally, the time required to measure one output absorption spectrum can be less than 1 ms.

This thesis describes the architecture and implementation of a novel 10-bit hybrid Analog to Digital Converter using Flash and Delay Line concepts. Flash ADCs employ power hungry comparators which increase the overall power consumption of a high resolution ADC. High resolution flash also requires precision analog circuit design. Delay line ADCs are based on digital circuits and operate at low power. Both Flash based ADCs and delay line based ADCs can be used to get a fast analog to digital conversion, but with limited resolution. These two approaches are combined to achieve a 10-bit resolution (4 bits using Flash and 6 bits using delay line) without compromising on speed and maintaining low power operation. Low resolution of Flash also helps in reducing the analog circuit design complexity of the voltage comparators. The ADC was capable of running at 100M samples/s, with an ENOB of 8.82 bits, consuming 8.59mW at 1.8V. / text