Quantum optical integrated circuits have heralded a paradigm shift in the realm of quantum information processing. Integrated photonics technology now empowers the creation of intricate optical circuits on single chips. While optical integrated circuits used to pose formidable challenges for numerous quantum applications, they have, in recent times, evolved to satisfy stringent requirements across a spectrum of research and industrial domains. Today, it is imperative to delve into research aimed at both crafting and preserving quantum properties within photonic substrates. Superimposed Bragg grating structures have emerged as valuable components within optical applications, poised to play pivotal roles in the development of integrated circuits. Nevertheless, these structures exhibit an inherent drawback in the form of dispersion, which can potentially compromise the preservation of quantum states. In this study, we meticulously scrutinize the physical attributes of these structures to elucidate the factors contributing to undesirable dispersion effects. We also investigate the correlation between two photons at the termination point of the structure. The superimposed Bragg grating structure under scrutiny boasts periods of both 1 and 3 micrometers, an overall length of 100 micrometers, and radiates at a wavelength of 1.55 micrometers. By subjecting photons to this medium individually or in tandem and analyzing their correlation function, we aim to pinpoint elements that effectively safeguard the quantum properties inherent in the system. This research endeavor is poised to yield valuable insights that will substantially influence the design of quantum integrated circuits, enhancing their efficacy in computational tasks and quantum information processing.
Quantum optical integrated circuits have heralded a paradigm shift in the realm of quantum information processing. Integrated photonics technology now empowers the creation of intricate optical circuits on single chips. While optical integrated circuits used to pose formidable challenges for numerous quantum applications, they have, in recent times, evolved to satisfy stringent requirements across a spectrum of research and industrial domains. Today, it is imperative to delve into research aimed at both crafting and preserving quantum properties within photonic substrates. Superimposed Bragg grating structures have emerged as valuable components within optical applications, poised to play pivotal roles in the development of integrated circuits. Nevertheless, these structures exhibit an inherent drawback in the form of dispersion, which can potentially compromise the preservation of quantum states. In this study, we meticulously scrutinize the physical attributes of these structures to elucidate the factors contributing to undesirable dispersion effects. We also investigate the correlation between two photons at the termination point of the structure. The superimposed Bragg grating structure under scrutiny boasts periods of both 1 and 3 micrometers, an overall length of 100 micrometers, and radiates at a wavelength of 1.55 micrometers. By subjecting photons to this medium individually or in tandem and analyzing their correlation function, we aim to pinpoint elements that effectively safeguard the quantum properties inherent in the system. This research endeavor is poised to yield valuable insights that will substantially influence the design of quantum integrated circuits, enhancing their efficacy in computational tasks and quantum information processing.
The impact of higher-order dispersion coefficients on the correlation function is a significant topic in quantum technology, particularly for transmission over dispersion-compensated optical fibres. This study focuses on using the standard deviation of the correlation function as a metric to assess the influence of higher-order dispersion coefficients. It demonstrates that the second and third orders of dispersion coefficients play a crucial role in this investigation. When the amplitude of the probability function of a single photon is broad, it should be considered within the context of the dispersive structure, such as in the case of Bragg grating. The concept behind dispersion management is to effectively correlate the entangled photons while filtering out the broad amplitude of the probability function of a single photon. Within the framework of this study, we find that the third-order dispersion coefficient in a Bragg grating, serving as a biphoton transmission medium, significantly affects the standard deviation of the correlation of entangled photons, leading to a decline in its value. Notably, whether the third-order dispersion coefficient is positive or negative contributes to this effect.
Abstract In the realm of quantum information processing and precision measurements, a range of non-classical effects based on entangled photon pairs are employed. Non-local dispersion cancellation is one of these properties, in which the second photon (idler) can be manipulated to cancel the effects of dispersion on the first photon (signal). In the present study, a thorough investigation is conducted into non-local dispersion cancellation by using excitation modes within a Bragg grating slab waveguide. We present a complete theoretical analysis of non-local dispersion cancellation for frequency-limited entangled photon pairs. For the analysis of the effect of dispersion cancellation, we use a spontaneous parametric down-conversion (SPDC) photon pair source with frequency correlation and anti-correlation as the entangled source. To evaluate the dispersion cancellation effect for information processing applications, the second correlation function is used and calculated as a practical and tangible metric. Considering different cases for Bragg Grating waveguide the results on both photons are extracted and discussed. Moreover, we will show that the physical parameters of the waveguide that the second photon is propagated inside will be effective in minimizing the width of the temporal correlation function. Hence, this study underscores the feasibility of achieving non-local dispersion cancellation through strategic optimization of optical and geometric parameters in the Bragg Grating waveguide, with potential implications for quantum information processing and high-resolution sensing endeavors.
The convergence of metamaterials and quantum optics heralds a transformative era in photonic technologies, poised to revolutionize applications ranging from information processing and imaging to sensing and beyond. This review explores the synergistic integration of metasurfaces—engineered sub-wavelength planar structures—and quantum optics, which exploits quantum mechanical principles to manipulate light at the most granular level. We outline the design principles, fabrication processes, and computational challenges involved in creating quantum metasurfaces, discussing both forward and inverse design approaches. Advances in nanofabrication and intelligent optimization techniques, such as machine learning and topology optimization, have enabled the development of metasurfaces with unparalleled control over electromagnetic waves. We examine recent progress in using quantum metasurfaces for single-photon and multi-photon generation, quantum imaging, and quantum sensing, showcasing how these innovations achieve unprecedented precision and novel functionalities. Additionally, we highlight the integration of metasurfaces into quantum light manipulation, emphasizing their role in enhancing wavefront shaping and entanglement control. By providing a comprehensive survey of current advancements and future research directions, this review highlights the vast potential of metasurfaces and quantum optics at the crossroads, setting the stage for next-generation technological innovations that will define the forthcoming decade.
The past two decades have witnessed tremendous advances and breakthroughs in quantum information science and technology, due mainly to the use of quantum physical resources such as coherence and entanglement. The formalization of the concept of universal quantum computing by D. Deutsch in 1985 has matured into commercial initiatives that aim to accelerate the physical implementation of a practical quantum computer. So far, such quantum technology has been pushed forward as information processors that are mainly on superconducting quantum bits (qubits) based. Other developments make use of quantum states of photons in conjunctions with other quantum registers based on electrons, atoms, molecules, artificial systems, between others. Although in any case, multiple qubit technologies are still under intense research and developments and the temperature and size of the quantum register are essential issues. However, all possible physical implementation of quantum information processing devices have in common the fundamental properties of quantum systems: interference, coherence, and entanglement. In this thesis, we concerned the study of quantum coherence and entanglement in qubits (encoded on the polarisation basis) and quantum materials (operating at room temperature) to analyze the role of quantum correlations and decoherence for information processing purposes. The current research is divided into two main parts, the first one begins with the analysis of the influence of a birefringent medium over the entanglement of a photonic qubit state. We employ a polarisation maintaining fiber (PMF) as a decohering environment to test the theoretical model in which the symmetry of the coupling between the qubit and environment defines the death and revival of the information correlations. This finding establishes a tool to keep the entanglement independent of the fiber length employing the symmetry properties of the physical system. Additionally, to demonstrate that the entanglement is not the only crucial factor in information schemes, we employ the prisoner’s dilemma game (in a two parameters strategy space and extended up to three) to evidence that quantum advantages in this protocol are by the quantum superposition instead of the entanglement of the physical system. Here we also pose an experimental setup with photons to verify our findings with photonic qubits. The second part of the thesis examines a novel nanomaterial which could serve up a bridge to the interaction of photons and electrons toward a physical representation of photonic qubits conditioned by external registers (as electrons or ions). The first stage in this direction considers the implementation of single photon emitters. However, previous to it is necessary to recognize the photophysical capabilities of the Perovskites as structure selected. As a complement, the novelty of this nanostructure allow us to give answers to some open questions in this characterization direction in the frame of this research. The MA-halide (methylammonium-halide) perovskites are structurally composed by small domains which ranging from nano to micrometer sizes presenting strong photoluminescence intermittency (blinking). We attribute this response to the Auger- nonradiative recombination of additional electrons photogenerated in a trap-filling process due to defects or ion movement. We verified this through the application of an absorbing layer (quencher) of charges of PCBM (Phenyl-C61-butyric acid methyl ester) resulting in considerably decreases in blinking. We also provide a novel technique for real-time observation of the ion movement effect over this material. Additionally, this behavior indicates appropriate conditions for the existence of a few emitters which are useful in quantum protocols and become a motivation to analyze and explain this phenomenon. Then, we prepare two chemical compositions of inorganic Perovskites with a high structural order to explore the necessary conditions to produce single emitter with this material. We visualized the samples through electron microscopy, and both systems were spectrally characterized decreasing dilutions up to observe emission intermittency. We verified the nonclassical behavior of the emission employing a Hanbury Brown-Twiss interferometer by measuring the degree of the second-order coherence correlation function. Finally, but not less important, the additional information presents the laboratories implemented during this doctoral research and the prototype of signals counting device to analyze temporal coincidences in correlated photonic events.
Silicon photonics is a dynamic research field of integrated optics. It allows to miniaturize numerous optical functionalities such as lasers, electro-optical modulators, routers, detectors, for telecom wavelengths, LIDAR, sensor, metrology or even spectroscopy, all while been able to propose large scale production high precision technologies. On another side, quantum optics suffers from difficulties to scale optical systems, requires extreme stability, perfect alignment, and many bulky optical elements, while solving these issues follows a natural path in integrated photonics. Development of integrated quantum photonics can thus open the door to cheap, powerful, and scalable systems for quantum cryptography, telecoms, and computation. In a significant way, quantum requirements are not the ones of classical circuits with respect to photonic components and circuits. The generation of quantum states indeed requires more than 100dB of pump laser rejection, while being able to manage ultra-low useful optical signals and get rid of on-chip optical noise. In this context, this thesis is dedicated to the study, dimension, realization, and characterization of silicon photonic components and circuits for quantum optics on a chip. The target goal is to generate entangled states in energy-time and manipulate them on chip. The qualification of the quantum properties is also explored to better understand the limitations of the silicon platform in the followed objectives. Another choice of this work is to stay in telecoms wavelength and aligned with the standard channels (ITU grid), to only use off-the-shelf components, all while been CMOS compatible and compliant with standard fabrication process, this to allow the possibility to produce on large scale.
Quantum technology is poised to enable a step change in human capability for computing, communications and sensing. Photons are indispensable as carriers of quantum information-they travel at the fastest possible speed and readily protected from decoherence. However, the system requires thousands of near-transparent components with ultra-low-latency control. To be implemented, a new paradigm photonic system is required: one with in-built coherence, stability, the ability to define arbitrary circuits, and a path to manufacturability. Silicon photonics has unparalleled density and component performance, which, with CMOS compatible fabrication, place it in a strong position for a scalable quantum photonics platform. This paper is a progress report on silicon quantum photonics, focused on developments in the past five years. We provide an introduction on silicon quantum photonic component and the challenges in the field, summarise the current state-of-the-art and identify outstanding technical challenges, as well as promising avenues of future research. We also resolve a conflict in the definition of Hong-Ou-Mandel interference visibility in integrated quantum photonic experiments, needed for fair comparison of photon quality across different platforms. Our aim is the development of scalability on the platform, to which end we point the way to ever-closer integration, toward silicon quantum photonic systems-on-a-chip.