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The main topic of this thesis is linear optics and the implementation of quantum operations (measurements, quantum channels, and unitary rotations) on optical systems. In the opening chapter the basic notions needed to understand the rest of the thesis will be explained. These notions include defining a quantum state, measurement, quantum channel and the linear optics tool set. The work in this thesis takes both fundamental and practical approaches to studying linear optical networks. For instance in the first chapter a proof is provided that shows that any unitary on a single mode Fock state can be realised with linear optics. The proof is constructive, however the approach to realising the unitary is not suitable for experimental implementation because it requires complicated ancilla states. As in the KLM proposal the procedure works only stochastically however by allowing the size of the ancilla to grow the probability of failure can be made arbitrarly small. Furthermore we investigate the realisation of arbitrary channels in a specific encoding that we call a $d$-rail encoding. The only ancilla state that we allow is a vacuum ancilliary state and further restrictions were considered (e.g. photon counting). A proof is provided that using these resources only random unitaries can be applied deterministically using linear optics. An expression for the optimal probability of success for realising more general channels with these resources is also discussed. As a final topic we also investigate the realisation of a quantum non-demolition measurement onto the dual rail qubit space. The investigation is a blend of both fundamental and practical approaches. To begin we employ a modified KLM-like procedure and show that the scheme can be realised perfectly but stochastically. The probability that the proper measurement is made can be made arbitrarly close to one using a suitably large ancilla state. In addition we consider an existing scheme \cite{gisin10a} which uses practical sources (two single photon sources) to perform the measurement. The scheme does not realise the true measurement but instead has a free parameter in it which is the transmittiviy of a beamsplitter. The measurement will project onto a space that has a vacuum component. By adjusting the transmittivity of this beamsplitter the vacuum component can be made arbitrarly small but only at the expense of the probability of success of the procedure. In this thesis a modification that can be made to eliminate the vacuum component without changing the sources is introduced. The modification is surprisingly simple and only involves the addition of a single beamsplitter. In the proposal for the original amplifier it was used in simulations for DIQKD that included device imperfections. To show the improvement of our modification these DIQKD simulations are reproduced using the modified amplifier and its results are compared to the results of the original amplifier.

The main topic of this thesis is linear optics and the implementation of quantum operations (measurements, quantum channels, and unitary rotations) on optical systems. In the opening chapter the basic notions needed to understand the rest of the thesis will be explained. These notions include defining a quantum state, measurement, quantum channel and the linear optics tool set. The work in this thesis takes both fundamental and practical approaches to studying linear optical networks. For instance in the first chapter a proof is provided that shows that any unitary on a single mode Fock state can be realised with linear optics. The proof is constructive, however the approach to realising the unitary is not suitable for experimental implementation because it requires complicated ancilla states. As in the KLM proposal the procedure works only stochastically however by allowing the size of the ancilla to grow the probability of failure can be made arbitrarly small. Furthermore we investigate the realisation of arbitrary channels in a specific encoding that we call a $d$-rail encoding. The only ancilla state that we allow is a vacuum ancilliary state and further restrictions were considered (e.g. photon counting). A proof is provided that using these resources only random unitaries can be applied deterministically using linear optics. An expression for the optimal probability of success for realising more general channels with these resources is also discussed. As a final topic we also investigate the realisation of a quantum non-demolition measurement onto the dual rail qubit space. The investigation is a blend of both fundamental and practical approaches. To begin we employ a modified KLM-like procedure and show that the scheme can be realised perfectly but stochastically. The probability that the proper measurement is made can be made arbitrarly close to one using a suitably large ancilla state. In addition we consider an existing scheme \cite{gisin10a} which uses practical sources (two single photon sources) to perform the measurement. The scheme does not realise the true measurement but instead has a free parameter in it which is the transmittiviy of a beamsplitter. The measurement will project onto a space that has a vacuum component. By adjusting the transmittivity of this beamsplitter the vacuum component can be made arbitrarly small but only at the expense of the probability of success of the procedure. In this thesis a modification that can be made to eliminate the vacuum component without changing the sources is introduced. The modification is surprisingly simple and only involves the addition of a single beamsplitter. In the proposal for the original amplifier it was used in simulations for DIQKD that included device imperfections. To show the improvement of our modification these DIQKD simulations are reproduced using the modified amplifier and its results are compared to the results of the original amplifier.

The future experimental programs both at FNAL and at CERN will have a strong focus on the search for new physics at the intensity frontier. In order to provide beams of unprecedented intensities to the various experiments at these labs, the booster accelerators in which the beams originate must perform far beyond their original design specifications. The optical properties of the booster accelerator lattices will need to be carefully controlled in order to deliver these high-intensity proton beams. This thesis presents the results of linear optics measurements made with unprecedented precision in the FNAL Booster and the CERN PS Booster using LOCO and K-modulation techniques. In the FNAL Booster, corrections to the observed optics distortions were also successfully implemented. The implications of these results for future high-intensity operations are discussed. / text

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Over the past few years, researchers have directed a significant amount of effort towards realizing tunable all-optical devices using nonlinear optical methods. It is now possible to exercise dynamic control of the group velocity of light traveling through a wide variety of material systems. The slow and fast light refer to situations in which the group velocity íg of an optical pulse through a dispersive material can be made to be smaller and larger, respectively, than the phase velocity vp = c/n. This ability could overcome the remaining challenge in current optical networks of storing and manipulating an optical signal directly in optical domain so as to avoid a bottleneck due to optical-to-electrical (O/E) and electrical-to-optical (E/O) conversions. The overall purpose of the dissertation is to study novel slow-light systems that provide controlled generation of large pulse delays relative to the pulse width with minimal pulse shape distortion by optimally design resonance profiles of such systems. The system design studies utilize several measures of performance such as the fractional delay, power throughput, and signal distortion under the limited system resource constraints. To this end, powerful data fidelity metrics are required to quantify the performance of tunable delay devices. Here, a new framework for measuring an information velocity and throughput is described and implemented using Shannon mutual information concepts. This new technique is used to investigate trends, trade-offs, and limits in slow light devices, which are physically sensible and in good agreement with analyses obtained using a conventional eye-opening(EO) metric. Using these information-theoretic and/or conventional metrics, we present the quantifying performance of gain-based stimulated Brillouin scattering (SBS) system in optical fibers as well as optical passive devices such as Fabry-Perot, fiber Bragg gratings, and ring resonators. It is shown that combining the SBS gain medium with these passive devices can compensate their respective disadvantages and thus increase delay performance without using additional resource of SBS pump power. The results show the possibility of achieving a fractional delay up to 10 at a signal bandwidth up to tens of GHz.

Dans le cadre de cette thèse un verre phosphate de zinc dopé avec des cations d’argent a été irradié par laser femtoseconde. Cette irradiation induit l’apparition dans le voxel de focalisation, d’une émission de fluorescence et une génération de second harmonique au sein du verre. La fluorescence a été attribuée à la création d’agrégats fluorescents composé d’une dizaine d’atomes d’argent. Une étude spectrale a été réalisée permettant de distinguer les différents types d’agrégats générés. Par ailleurs, la génération de seconde harmonique est attribuée à la présence d’un champs électrique enterré dans la zone irradié par effet EFISH (electric field induced second harmonic). La direction et la répartition de ce champ électrique, ont été étudié optiquement et conduisent à sa représentation spatiale.Les effets des paramètres expérimentaux, tels que le nombre d’impulsions laser, l’énergie par impulsion, la température du verre et le recuit sur les caractéristiques de la GSH et de la fluorescence, ont été étudiés. Enfin un processus global est proposé, expliquant les différentes étapes de la structuration, de la création du champ enterré par migration d’électrons à la réduction des cations d’argent et la croissance des agrégats. / In this work, a phosphate-zinc glass doped with silver ions was irradiated with a femtosecond laser. This irradiation causes the appearance of sub-micron features in the glass. Those features exhibit fluorescence and second harmonic generation. Fluorescence is linked to the aggregations of silver clusters in the glass. Second Harmonic Generation is linked to the creation of a buried electric field inducing an EFISHG effect.Polarization and spectroscopic studies were performed on these features. Those studies allowed us to produce a three-dimensional representation of the features. A phenomenological model, from the interaction of the laser pulses with the glass, to the movement of charges enabling the buried field, is developed to explain the overall process, therefore linking the migration of the electrons to the reduction of silver ion and the cluster growth.

Nesta dissertaÃÃo e proposto um sistema de correÃÃo de erro quÃntico para estados coerentes de luz e um sistema Ãptico completo para a teleportaÃÃo probabilÃstica de qubits codificados na polarizaÃÃo de um fÃton. O trabalho se inicia com a analise de correÃÃo de erro quÃntico com a utilizaÃÃo de redundÃncias. Depois, e apresentada uma forma de correÃÃo de erros utilizando qubits do tipo time-bin e sem acrÃscimo de redundÃncias. Com base nesta abordagem, foi proposto um sistema de correÃÃo de erro quÃntico passivo, isto e, que nao precisa de controle externo de sincronizaÃÃo, para sistemas de comunicaÃÃes quÃnticas que utilizam estados coerentes de luz, utilizando apenas dispositivos opticos lineares. E mostrado, tambÃm, que o sistema de correÃÃo de qubits individuais pode ser usado para corrigirem estados bipartes de qubits. Em seguida, e analisada a teleportaÃÃo de estados quÃnticos e proposto um sistema probabilÃstico de teleportacao de estados quÃnticos de polarizaÃÃo de fÃtons isolados utilizando dispositivos Ãpticos lineares. Por fim, os tÃpicos de correÃÃo de erro e teleportacao sÃo unidos na proposiÃÃo de um sistema probabilÃstico de teleportacao empregando um sistema de correÃÃo de erros na distribuiÃÃo do par de fÃtons entrelaÃados. / In this dissertation it is considered a quantum error correction system for coherent states of light and a complete optical system for probabilistic teleportation of single-photon polarization encoded qubit. Initially, the quantum error correction with the use of redundancy is analyzed. After that, it is presented a form of error correction using time-bin qubit without redundancies. Based on this last approach, a passive quantum error correction system, that is, without external control and synchronization, for quantum communication system employing coherent states, using only linear optical devices, is proposed. It is shown that the quantum error correction system also works for bipartite states of qubits. Following, the teleportation of quantum states is analyzed and an optical system for probabilistic teleportation of single-photon polarization encoded qubit, using only linear optical devices, is proposed. Finally, the error correction and teleportation topics are put together in the proposal of a probabilistic teleportation system using an error correction system for distribution of the entangled pair of photons

Optical methods can provide useful tissue characterization tools. For this project, two-photon microscopy and polarized light examinations (polarimetry) were used to assess the organizational state of myocardium in healthy, infarcted, and stem-cell regenerated states. Two-photon microscopy visualizes collagen through second-harmonic generation and myocytes through two-photon excitation autofluorescence, providing information on the composition and structure/organization of the tissue. Polarimetry measurements yield a value of linear retardance that can serve as an indicator of tissue anisotropy, and with a dual-projection method, information about the anisotropy axis orientation can also be extracted. Two-photon microscopy results reveal that stem-cell treated tissue retains more myocytes and structure than infarcted myocardium, while polarimetry findings suggest that the injury caused by temporary ligation of a coronary artery is less severe and more diffuse that than caused by a permanent ligation. Both these methods show potential for tissue characterization.