This thesis presents a Hamiltonian formulation of the electromagnetic fields in structured (inhomogeneous) media of arbitrary dimensionality, with arbitrary material dispersion and absorption consistent with causality. The method is based on an identification of the photonic component of the polariton modes of the system. Although the medium degrees of freedom are introduced in an oscillator model, only the macroscopic response of the medium appears in the derived eigenvalue equation for the polaritons. For both the discrete transparent-regime spectrum and the continuous absorptive-regime spectrum, standard codes for photonic modes in nonabsorptive systems can easily be leveraged to calculate polariton modes. Two applications of the theory are presented: pulse propagation and spontaneous parametric down-conversion (SPDC). In the propagation study, the dynamics of the nonfluctuating part of a classical-like pulse are expressed in terms of a Schr\"{o}dinger equation for a polariton effective field. The complex propagation parameters of that equation can be obtained from the same generalized dispersion surfaces typically used while neglecting absorption, without incurring additional computational complexity. As an example I characterize optical pulse propagation in an Au/MgF$_2$ metallodielectric stack, using the empirical response function, and elucidate the various roles of Bragg scattering, interband absorption and field expulsion. Further, I derive the Beer coefficient in causal structured media. The SPDC calculation is rigorous, captures the full 3D physics, and properly incorporates linear dispersion. I obtain an expression for the down-converted state, quantify pair-production properties, and characterize the scaling behavior of the SPDC energy. Dispersion affects the normalization of the polariton modes, and calculations of the down-conversion efficiency that neglect this can be off by 100$\%$ or more for common media regardless of geometry if the pump is near the band edge. Furthermore, I derive a 3D three-wave group velocity walkoff factor; due to the interplay of a topological property with a symmetry property, I show that even if down-conversion is into a narrow forward cone, neglect of the transverse walkoff can lead to an overestimate of the SPDC energy by orders of magnitude.

This thesis describes various methods for producing photon pairs from waveguides. It covers relevant topics such as waveguide coupling and phase matching, along with the relevant measurement techniques used to infer photon pair production. A new proposal to solve the phase matching problem is described along with two conceptual methods for generating entangled photon pairs. Photon pairs are also experimentally demonstrated from a third novel structure called a Bragg Reflection Waveguide (BRW). The new proposal to solve the phase matching problem is called Directional Quasi-Phase Matching (DQPM). It is a technique that exploits the directional dependence of the non-linear susceptiblity ($\chi^{(2)}$) tensor. It is aimed at those materials that do not allow birefringent phase-matching or periodic poling. In particular, it focuses on waveguides in which the interplay between the propagation direction, electric field polarizations and the nonlinearity can change the strength and sign of the nonlinear interaction periodically to achieve quasi-phasematching. One of the new conceptual methods for generating entangled photon pairs involves a new technique that sandwiches two waveguides from two differently oriented but similar crystals together. The idea stems from the design of a Michelson interferometer which interferes the paths over which two unique photon pair processes can occur, thereby creating entanglement in any pair of photons created in the interferometer. By forcing or sandwiching the two waveguides together, the physical space that exists in the standard Micheleson type interferometer is made non-existent, and the interferometer is effectively squashed. The result is that the two unique photon pair processes actually occupy the same physical path. This benefits the stability of the interferometer in addition to miniaturizing it. The technical challenges involved in sandwiching the two waveguides are briefly discussed. The main result of this thesis is the observation of photon pairs from the BRW. By analyzing the time correlation between two single photon detection events, spontaneous parametric down conversion (SPDC) of a picosecond pulsed ti:sapph laser is demonstrated. The process is mediated by a ridge BRW. The results show evidence for type-0, type-I and type-II phase matching of pump light at 783nm, 786nm and 789nm to down converted light that is strongly degenerate at 1566nm, 1572nm, and 1578nm respectively. The inferred efficiency of the BRW was 9.8$\cdot$10$^{-9}$ photon pairs per pump photon. This contrasts with the predicted type-0 efficiency of 2.65$\cdot$10$^{-11}$. This data is presented for the first time in such waveguides, and represents significant advances towards the integration of sources of quantum information into the existing telecommunications infrastructure.

The experiments described in this thesis form an investigation into the path towards establishing the requirements of quantum computing in a linear optical system. Our qubits are polarisation encoded photons for which the basic operations of quantum computing, single qubit rotations, are a well understood problem. The difficulty lies in the interaction of photons. To achieve these we use measurement induced non-linearities. The first experiment in this thesis describes the thorough characterisation of a controlled-sign gate based on such non-linearities. The photons are provided as pairs generated through parametric down-conversion, and as such share correlations unlikely to carry over into large scale implementations of the future. En route to such larger circuits, a characterisation of the actions of the controlled-sign gate is conducted, when the input qubits have been generated independently from each other, revealing a large drop in process fidelity. To explore the cause of this degradation of the gate performance a thorough and highly accurate model of the gate is derived including the realistic description of faulty circuitry, photon loss and multi-photon emission by the source. By simulating the effects of the various noise sources individually, the heretofore largely ignored multi-photon emission is identified as the prime cause of the degraded gate performance, causing a drop in fidelity nearly three times as large as any other error source. I further draw the first comparison between the performance of an experimental gate to the error probabilities per gate derived as thresholds for fault-tolerant quantum computing. In the absence of a single vigourous threshold value, I compare the gate performance to the models that yielded the highest threshold to date as an upper bound and to the threshold of the Gremlin-model, which allows for the most general errors. Unsurprisingly this comparison reveals that the implemented gate is clearly insufficient, however just remedying the multi-photon emission error will allow this architecture to move to within striking distance of the boundary for fault-tolerant quantum computing. The utilised methodology can be applied to any gate in any architecture and can, combined with a suitable model of the noise sources, become an important guide for developments required to achieve fault tolerant quantum computing. The final experiment on the path towards linear optical quantum computing is the demonstration of a pair of basic versions of Shor's algorithm which display the essential entanglement for the algorithm. The results again highlight the need for extensive measurements to reveal the fundamental quality of the implemented algorithm, which is not accessible with limited indicative measurements. In the second part of the thesis, I describe two experiments on other forms of entanglement by extending the actions of a Fock-State filter, a filter that is capable of attenuating single photon states stronger than multi-photon states, to produce entangled states. Furthermore this device can be used in conjunction with standard wave-plates to extend the range of operations possible on the bi-photonic qutrit space, showing that this setup suffices to produce any desired qutrit state, thereby giving access to new measurement capabilities and in the process creating and proving the first entanglement between a qubit and a qutrit.

The experiments described in this thesis form an investigation into the path towards establishing the requirements of quantum computing in a linear optical system. Our qubits are polarisation encoded photons for which the basic operations of quantum computing, single qubit rotations, are a well understood problem. The difficulty lies in the interaction of photons. To achieve these we use measurement induced non-linearities. The first experiment in this thesis describes the thorough characterisation of a controlled-sign gate based on such non-linearities. The photons are provided as pairs generated through parametric down-conversion, and as such share correlations unlikely to carry over into large scale implementations of the future. En route to such larger circuits, a characterisation of the actions of the controlled-sign gate is conducted, when the input qubits have been generated independently from each other, revealing a large drop in process fidelity. To explore the cause of this degradation of the gate performance a thorough and highly accurate model of the gate is derived including the realistic description of faulty circuitry, photon loss and multi-photon emission by the source. By simulating the effects of the various noise sources individually, the heretofore largely ignored multi-photon emission is identified as the prime cause of the degraded gate performance, causing a drop in fidelity nearly three times as large as any other error source. I further draw the first comparison between the performance of an experimental gate to the error probabilities per gate derived as thresholds for fault-tolerant quantum computing. In the absence of a single vigourous threshold value, I compare the gate performance to the models that yielded the highest threshold to date as an upper bound and to the threshold of the Gremlin-model, which allows for the most general errors. Unsurprisingly this comparison reveals that the implemented gate is clearly insufficient, however just remedying the multi-photon emission error will allow this architecture to move to within striking distance of the boundary for fault-tolerant quantum computing. The utilised methodology can be applied to any gate in any architecture and can, combined with a suitable model of the noise sources, become an important guide for developments required to achieve fault tolerant quantum computing. The final experiment on the path towards linear optical quantum computing is the demonstration of a pair of basic versions of Shor's algorithm which display the essential entanglement for the algorithm. The results again highlight the need for extensive measurements to reveal the fundamental quality of the implemented algorithm, which is not accessible with limited indicative measurements. In the second part of the thesis, I describe two experiments on other forms of entanglement by extending the actions of a Fock-State filter, a filter that is capable of attenuating single photon states stronger than multi-photon states, to produce entangled states. Furthermore this device can be used in conjunction with standard wave-plates to extend the range of operations possible on the bi-photonic qutrit space, showing that this setup suffices to produce any desired qutrit state, thereby giving access to new measurement capabilities and in the process creating and proving the first entanglement between a qubit and a qutrit.

The experiments described in this thesis form an investigation into the path towards establishing the requirements of quantum computing in a linear optical system. Our qubits are polarisation encoded photons for which the basic operations of quantum computing, single qubit rotations, are a well understood problem. The difficulty lies in the interaction of photons. To achieve these we use measurement induced non-linearities. The first experiment in this thesis describes the thorough characterisation of a controlled-sign gate based on such non-linearities. The photons are provided as pairs generated through parametric down-conversion, and as such share correlations unlikely to carry over into large scale implementations of the future. En route to such larger circuits, a characterisation of the actions of the controlled-sign gate is conducted, when the input qubits have been generated independently from each other, revealing a large drop in process fidelity. To explore the cause of this degradation of the gate performance a thorough and highly accurate model of the gate is derived including the realistic description of faulty circuitry, photon loss and multi-photon emission by the source. By simulating the effects of the various noise sources individually, the heretofore largely ignored multi-photon emission is identified as the prime cause of the degraded gate performance, causing a drop in fidelity nearly three times as large as any other error source. I further draw the first comparison between the performance of an experimental gate to the error probabilities per gate derived as thresholds for fault-tolerant quantum computing. In the absence of a single vigourous threshold value, I compare the gate performance to the models that yielded the highest threshold to date as an upper bound and to the threshold of the Gremlin-model, which allows for the most general errors. Unsurprisingly this comparison reveals that the implemented gate is clearly insufficient, however just remedying the multi-photon emission error will allow this architecture to move to within striking distance of the boundary for fault-tolerant quantum computing. The utilised methodology can be applied to any gate in any architecture and can, combined with a suitable model of the noise sources, become an important guide for developments required to achieve fault tolerant quantum computing. The final experiment on the path towards linear optical quantum computing is the demonstration of a pair of basic versions of Shor's algorithm which display the essential entanglement for the algorithm. The results again highlight the need for extensive measurements to reveal the fundamental quality of the implemented algorithm, which is not accessible with limited indicative measurements. In the second part of the thesis, I describe two experiments on other forms of entanglement by extending the actions of a Fock-State filter, a filter that is capable of attenuating single photon states stronger than multi-photon states, to produce entangled states. Furthermore this device can be used in conjunction with standard wave-plates to extend the range of operations possible on the bi-photonic qutrit space, showing that this setup suffices to produce any desired qutrit state, thereby giving access to new measurement capabilities and in the process creating and proving the first entanglement between a qubit and a qutrit.

Submitted by Haroudo Xavier Filho (haroudo.xavierfo@ufpe.br) on 2016-03-22T17:58:05Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dissertacao_bismarck_final_estudo_da_conversao_descendente.pdf: 9102695 bytes, checksum: f43bbe4be7ee1b5ccf50bbd67bdbabc1 (MD5) / Made available in DSpace on 2016-03-22T17:58:05Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dissertacao_bismarck_final_estudo_da_conversao_descendente.pdf: 9102695 bytes, checksum: f43bbe4be7ee1b5ccf50bbd67bdbabc1 (MD5) Previous issue date: 2015-04-13 / CAPES, CNPq, FACEPE / C elulas solares apresentam-se como uma alternativa vi avel para a gera c~ao de energia limpa e renov avel pela sua capacidade de convers~ao da energia solar em el etrica atrav es do efeito fotovoltaico. Entretanto, um dos fatores limitantes na utiliza c~ao deste tipo de energia tem sido a incompatibilidade espectral, a qual implica que apenas uma determinada parte do espectro solar seja efetivamente utilizado no processo de convers~ao fotovoltaica. Entre os diversos materiais fot^onicos, pesquisas em materiais dopados com ons de Terras Raras capazes de realizar a convers~ao de f otons de infravermelho para vis vel-UV ou vice-versa tem sido realizadas. Em aplica c~oes fotovoltaicas, este efeito pode melhorar a coleta da radia c~ao solar. Para a realiza c~ao desta tarefa dois mecanismos s~ao utilizados: Convers~ao Ascendente de Frequ^encia e Convers~ao Descendente de Frequ^encia. Este trabalho teve como objetivo estudar as propriedades espectrosc opicas e o mecanismo de Convers~ao Descendente de Frequ^encia em vidros dopados com os ons de Terras Raras Tb3+/Yb3+, Eu3+ e Er3+, e veri car suas poss veis aplica c~oes no melhoramento da e ci^encia de c elulas solares. A mesma matriz hospedeira foi utilizada. O estudo das propriedades espectrosc opicas foi realizado atrav es de medidas de absor c~ao, luminesc^encia e evolu c~ao temporal da luminesc^encia. Observamos o processo de convers~ao descendente de frequ^encia com emiss~ao no infravermelho, regi~ao que as c elulas solares de sil cio cristalino possuem maior e ci^encia, com excita c~ao em 355nm, que promoveu uma maior e ci^encia, e 482nm. Em seguida, para as matrizes dopadas com ons de Tb3+/Yb3+, foi determinado o mecanismo gerador do processo de convers~ao descendente de frequ^encia e a e ci^encia de transfer^encia de energia. Foi obtida uma e ci^encia de transfer^ encia de energia m axima de 112,7%. Para as matrizes dopadas com Eu3+ e Er3+ foram realizadas medidas de luminesc^encia com excita c~ao via laser de 482nm. Como aplica c~ao, foram realizadas medidas el etricas, para c elulas convencionais de Si e GaP, usando como fonte de radia c~ao um simulador solar com ltro AM 1.5. Os resultados foram avaliadas na presen ca e aus^encia dos vidros dopados com ons de Terras Raras na superf cie da c elula solar. Foi observado um aumento na e ci^encia de convers~ao fotovoltaica das c elulas de sil cio cobertas pelos vidros dopadas com 1%Tb3+ e 1%Eu3+ em rela c~ao a matriz sem dopagem. / Solar cells are shown as a viable alternative for generation renewable and clean energy due their ability of converter solar power in electric power by the photovoltaic e ect. However, one of the limitant facts to use photovoltaic devices to make electricity is spectral mismatch, that implies only a speci c range of solar spectrum is e ectively used in the process of photovoltaic conversion. Between the several photonics devices, research in Rare Earth ions doped materials able to do the conversion of infrared photons in visible-UV photons or the opposite have been performed. In photovoltaic applications, this e ect can enhance the harvesting of solar light. To realize this task two mechanism are used: Frequency up-conversion and frequency down-conversion. This work had the goal of study the spectroscopic properties and the Frequency Down-conversion mechanism in Tb3+/Yb3+, Eu3+ and Er3+ Rare Earth doped glasses, and check their possible applications to enhance solar cell e ciency. The same host matrix are used. The spectroscopic study was realized by luminescence, absorption, and temporal evolution luminescence measurements. We observe the frequency down-conversion and infrared emission, zone that crystaline silicon solar cell have the best e ciency, with 355nm excitation, that promote the best e ciency, and 482nm excitation. Then, for host matrix doped with Tb3+/Yb3+ ions, was determined the generation mechanism of frequency down-conversion and energy transfer e ciency. The major energy transfer e ciency was 112,7%. For host matriz doped with Eu3+ and Er3+ ions, was realized luminescence measurements with 482nm excitaion. Was realized electric measurements as applications in Si and GaP cells, solar simulator with AM 1.5 lter was used as radiation source. The results were evaluated with and without Rare Earth ions doped glasses on the surface of solar cell. We observed the enhancement of photovoltaic conversion when the silicon solar cell are covered with by glasses doped with 1%Tb3+ and 1%Eu3+ with respect to matrix covered.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-02-13T13:44:40Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dissertação final.pdf: 3576056 bytes, checksum: 4650485627f1eb13bb131bcbf6ab588a (MD5) / Made available in DSpace on 2017-02-13T13:44:40Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) dissertação final.pdf: 3576056 bytes, checksum: 4650485627f1eb13bb131bcbf6ab588a (MD5) Previous issue date: 2014-03-28 / CAPES / A criação de estados emaranhados em polarização permite testar experimentalmente questões fundamentais da mecânica quântica, tais como os argumentos de EPR sobre a incompletezadateoriaquântica,atravésdadesigualdadeCHSH.Alémdisso,essesestados emaranhados, têm potenciais de aplicações como, por exemplo, em computação quântica e criptografia quântica. Neste trabalho, se estuda uma fonte muito eficiente para a produção de estados de fótons emaranhados em polarização baseada em um interferômetro de tipo Sagnac. Estes fótons correlacionados são criados em um cristal não linear PPKTP mediante o processo de conversão paramétrica descendente (PDC) tipo-II, quando o cristal é bombeado por pulsos de fentossegundos. Verificando as correlações das medidas de polarização produzidas por esta fonte, observamos fortes violações das desigualdades de Bell para estados de polarização, isto é, verificamos a desigualdade CHSH. / Creation of polarization entangled states allows experimentally to test fundamental properties of quantum mechanics, such as the EPR argument about the incompleteness of the quantum theory, through CHSH inequality; in addition to potential applications as in quantum computing and quantum cryptography. This work studies a very efficient sourceofphotonentangledstatesofpolarizationbasedonaSagnacinterferometer. These photons are created from a nonlinear PPKTP crystal pumped by fentosecond pulses by theprocessofparametricdown-conversion(PDC)type-IIpumpedbyfemtosecondpulses. Analysing correlations of polarization measurements produced by this source we observed strong violations of Bell inequalities for the polarization states, i.e, CHSH inequality.

Down-conversion (DC) and down-shifting (DS) layers are optical layers mounted on the top surface of a solar cell that can potentially increase the solar cell efficiency. The effect of DC and DS layers to enhance the performance of single-junction solar cells has been studied by means of simulation and experimental work. In this thesis a model is developed to study the effects of DC and DS layers by modifying the incident spectrum. The effect of the layers on ideal cells as well as commercial grade silicon and CIGS solar cells that are modeled in a device simulator is examined. Silicon nanocrystals (Si-nC) embedded in a silicon dioxide matrix to act as a DS layer were fabricated and characterized at McMaster University as part of this project. The measured optical properties as well as the photoluminescence measurements are used as input parameters to the optical model. The enhancement due to the Si-nC when coupled to silicon and CIGS solar cells is explored. Beside the DC and DS effects, there is also disturbance to the surface reflections due to the addition of a new layer to the top surface and is referred to as antireflection coating (ARC) effect. For the simulated silicon solar cell under the standard AM1.5G spectrum (1000W/m2), a maximum increase in Jsc of 8.4% is achieved for a perfect DS layer as compared to a reference cell, where 7.2% is due to ARC effect and only 1.2% is due to DS effect. On the other hand, there is an increase in Jsc of 19.5% for the CIGS solar cell when coupled to a perfect DS layer. The DS effect is dominant with 18%, while the ARC effect contributes only 1.5% to the total Jsc enhancement. Accurately characterizing DS layers coupled to solar cell requires knowledge of optical properties of the complete structure. Internal quantum efficiency is an important tool for characterizing DS systems, nevertheless, it is rarely reported. In addition, the ARC effect is not experimentally decoupled from the DS effect. In this work, a straightforward method for calculating the active layer contribution that minimizes error by subtracting optically-modeled electrode absorption from experimentally measured total absorption.

Cette thèse porte sur les applications optiques de films d’oxynitrures de silicium dopés cérium et co-dopés cérium-ytterbium élaborés par pulvérisation cathodique magnétron radiofréquence. Les paramètres de dépôt ont été optimisés afin d’obtenir une intense émission visible à l’œil nu des ions Ce3+ dans la matrice hôte SiOxNy. Il est démontré que le flux d’azote est un paramètre crucial pour obtenir cette émission. Nous avons montré aussi que les ions Ce3+ peuvent être incorporés en grande quantité dans cette matrice, sans clusterisations jusqu’à de très hautes températures de recuits (1200°C). Ces excellentes propriétés optiques ont mené à une première application : la tentative d’élaboration de DEL bleue. Les premiers résultats obtenus montrent une électroluminescence peu intense, mais restent encourageants pour une étude plus approfondie. La deuxième application étudiée est le développement de couches à conversion de fréquence basse pour augmenter le rendement des cellules solaires à base de silicium. En effet les cellules solaires sont limitées par le recouvrement du spectre solaire et la plage d’absorption de la cellule. L’élaboration de films SiOxNy co-dopés Ce/Yb pour convertir un photon ultra-violet (300-400 nm) en deux photons infra-rouges (980 nm) permet de passer outre la limite théorique des cellules solaires. Les systèmes élaborés montrent une émission des ions Yb3+ en présence d’ions Ce3+ dans la matrice hôte SiOxNy. Les ions Ce3+ permettent d’excités les ions Yb3+ sur une large gamme spectrale et le mécanisme de transfert d’énergie entre ces deux terres rares est détaillé. Un rendement de conversion de 185% est obtenu pour la plus forte concentration en ions Yb3+. Pour améliorer ce système, l'ajout de miroirs de Bragg entre la couche à conversion et le substrat de silicium, représentant la cellule solaire, a été étudié théoriquement. Leur but est double : maximiser le flux de photons ultraviolets piégé dans la couche à conversion de fréquence et transmettre un maximum de photons infrarouges, qui sont facilement absorbables, vers la cellule solaire. / This thesis is dedicated to cerium doped and cerium-ytterbium co doped oxynitride silicon films optical applications grown by radio frequency magnetron sputtering. Growth parameters have been optimized in order to obtain a strong cerium emission visible to the naked eye in the matrix host SiOxNy, especially the nitrogen flux has a dominant role. We showed that cerium ions have a high solubility without clustering at very high annealing temperature (1200°C). Those excellent properties lead to a first application: the elaboration of blue LED. First results show a weak electroluminescence signal but are still encouraging for further study. The second application is the elaboration of frequency conversion layers to increase the efficiency of Si based solar cell. Indeed solar cell are limited by the mismatch between the solar spectrum and the cell absorption range. The elaboration of Ce/Yb co doped SiOxNy films to convert a UV photon (300-400 nm) into two infrared photons (980 nm) allows to overcome the solar cell theoretical limit. Layers grown show an Yb3+ ion emission in presence of Ce3+ ions in the host matrix SiOxNy. Ce3+ ions sensitize Yb3+ ions on a large spectral range and their cooperative energy transfer mechanism is detailed. An efficiency of 185% is obtained for the higher dopants atomic concentration. In order to improve this system, the effect of adding Bragg mirrors placed between the conversion layer and the silicon substrate, which represents the solar cell, is theoretically studied. Their aim is double: increase the maximum flux of UV photons trapped in the frequency conversion layer and transmit a maximum of infrared photons, which are easily absorbable, toward the solar cell.

We explore the optical parametric amplifier, an optical device where a pump field creates a pair of lower-frequency fields: signal and idler. The pump field is usually treated classically, but this thesis focuses on scenarios where the pump must be treated quantum mechanically. One of these scenarios is the growing field of nonlinear interferometry, where the fundamental sensitivity of a probed relative phase can beat the classical bounds and reach the maximum limit allowed by quantum mechanics, the Heisenberg limit. Indeed, we show that a fully quantum nonlinear interferometer displays a Heisenberg scaling in terms of the mean number of input pump photons. This result goes beyond the well-accepted Heisenberg scaling with respect to the down-converted photons inside the interferometer, which predicts unphysical phase sensitivities starting at a particular input pump energy. Our theoretical findings are particularly useful when designing a nonlinear interferometer with bright pump fields or optimized optical parametric amplifiers for quantum metrology and quantum imaging applications. The quantum nature of the pump field may also play a central role concerning other physical phenomena, like Hawking radiation in the context of black holes. As suggested by several authors, both the optical parametric amplifier and Hawking radiation comprise the creation of fundamental particle pairs. Thus, if the optical parametric amplifier is fully treated quantum mechanically, we may get insight into an open problem in modern physics, namely the black hole information paradox. According to this paradox, the information stored in a black hole can be destroyed once the black hole has evaporated by emitting Hawking radiation, contradicting quantum mechanics. Despite the experimental efforts to build systems that reproduce event horizons and gravitational effects in the laboratory, the evaporation of black holes due to the emission of Hawking radiation remains a challenging task. In this thesis, we experimentally investigate the impact of an evolving pump field in an optical parametric amplifier by optimizing a parametric down-conversion process. We measure the pump and signal photon number properties, finding that the pump field gets chaotic and the signal coherent when the pump displays some sizeable depletion. We arrive at similar conclusions about the pump field from its measured Wigner function. Our experiment is the first step towards a successful experiment that could suggest that information in the black hole is not destroyed but encoded in the emitted Hawking radiation starting at some point in the black hole evolution. We finally discuss further experimental improvements to investigate the parallel between the optical parametric amplifier and Hawking radiation.