Crystalline materials for microresonator-based quantum optics

Clément Christian Javerzac-Galy
EPFL, 2019
Thèse EPFL

Résumé

Hybrid quantum systems are composed of different physical components that can perform simultaneously several tasks such as quantum computing, quantum sensing and quantum communication. Photons are at the core of many of the functionalities of these systems. Photons of various wavelengths are better suited for different applications: microwave for quantum information processing, mid-infrared for sensing and visible for transmitting quantum information. The ability to study, understand and control these photons is key for this purpose. Nonlinear processes are necessary to implement some of these tasks or to connect different quantum systems. Single-crystal materials, with their unique properties, provide a promising source of nonlinearities for classical and quantum photonics. The integration of crystalline materials with optical microresonators enhances the physical effects of interest for the different applications.

This thesis explores the innovative use of new materials and microresonator designs. Three main results are presented. First, a device architecture capable of direct and efficient quantum microwave-to-optical conversion. Second, a method to fabricate uncoated chalcogenide tapered fibres and to study the properties of crystalline microresonators in the mid-infrared spectral window. Third, the coupling of the excitonic emission of atomically-thin van der Waals crystals to microcavities. The findings of this thesis provide the technological basis for design and fabrication of new chipscale microresonator based devices.

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https://infoscience.epfl.ch/record/265866?ln=fr

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Clément Christian Javerzac-Galy
EPFL, 2019
Thèse EPFL

Résumé

Official source

https://infoscience.epfl.ch/record/265866?ln=fr

À propos de ce résultat

Concepts associés (17)

Concepts associés

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Publications associées (8)

Publications associées

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Dissipation as a resource in circuit quantum electromechanics

László Dániel Tóth

A primary challenge in quantum science and technology is to isolate the fragile quantum states from their environment in order to prevent the irreversible leakage of energy and information which causes decoherence. In the late 1990s, however, a new paradigm emerged, in which the environment itself, as well as the coupling to this environment of the quantum state, are engineered in ways which, counterintuitively, facilitate the creation and stabilization of desired quantum properties. This paradigm, coined reservoir engineering, has been pursued experimentally in various implementations, in which the states of trapped ions, atomic clouds or artificial atoms based on superconducting circuits were driven into a desired target state using a dissipative reservoir. In all these cases, the cold electromagnetic environment served as the engineered reservoir, capitalizing on the tremendous progress in the ability to shape the modes of the electromagnetic field using masers and lasers. In optomechanics, which is the study of the coupling between light and mechanical motion, a similar scenario has been prevalent. Light is used to read out and control the mechanical motion, and in the past few years, various optomechanical architectures both in the optical and microwave domain have enabled to push mechanical systems into the quantum regime. These results can be interpreted in the context of reservoir engineering: cooling and many other optomechanical phenomena exploit the cold, dissipative nature of light. This thesis reports on the development of a multimode superconducting circuit with a mechanically compliant element - fitting into the field of circuit cavity electromechanics -, with which we pursue two themes. In the first set of experiments, reversing the roles of dissipation described above, we engineer the mechanical oscillator into a cold, dissipative environment for microwave light. The mechanical element is the fundamental mode of a free-standing top electrode of a capacitor, 100 nm thick and 32 micron in diameter made of aluminum with an effective mass of around 170 pg, vibrating at a resonance frequency of 5.5 MHz. The dissipative mechanical reservoir is prepared using an auxiliary microwave mode with engineered parameters.We utilize it to control the properties - in particular, the susceptibility - of the electromagnetic field and to perform low-noise amplification close to the quantum limit. The noise analysis reveals that the reservoir is close to its quantum ground state with a mean thermal occupation number well below 1, demonstrating its utility as a resource in the quantum regime. We also show that the system can be driven to the parametric instability threshold, above which self-sustained oscillations of the microwave field (masing) is observed. Finally, we demonstrate injection locking of the maser using an external seed pump. In a second set of experiments, a similar electromechanical circuit is used to implement a microwave isolator based on optomechanical interactions. The overarching theme is that dissipation of the mechanical oscillator, albeit intrinsic and not engineered via an auxiliary mode s a key ingredient for the device to function as a nonreciprocal frequency converter and isolator. In these experiments, an additional mechanical mode is used, such that a 4-mode optomechanical plaquette is realized.

EPFL2018

Chargement

Optical fibers have reshaped the technological landscape, from optical networks and high-speed data communication to in situ imaging and non-invasive surgery methods. The revolution allowed by these fibers has been made possible by its fabrication method, the thermal drawing process, which combines high scalability and nanoscale fabrication accuracy. Despite tremendous successes, silica step-index and photonic crystal fibers have held intrinsic limitations due to their mechanical rigidity and fragility, limiting their possible applications . There is however an increasing demand for optical fibers that could guide light efficiently while sustaining large deformations in fields like robotics, smart textiles and the automotive world. Other fields in sensing, helath care or advanced textiles could benefit from soft fibers that could display tunable optical effects. Techniques like lithography and molding have proven valuable to fabricate complex elastomeric photonic fibers, but their limited scalability intrinsically limits their use in several fields of application. On the other hand, scalable fabrication techniques like extrusion guarantee the desired throughput but fail to deliver the architectural complexity required to realize softfibers advanced optical properties. In this thesis, we propose to exploit the thermal drawing process to realize different types of soft and highly stretchable optical fibers, from the classic step-index architecture to 1D photonic crystal fibers, liquid core fibers and 2D photonic crystal fibers. To achieve this overall objective, we first establish a theoretical framework to evaluate the material requirements from the rheological, optical and mechanical point of view. After selecting the materials, we develop a step-by-step fabrication process that starts from the material pellets and ends with the fabrication of meters of elastomeric photonic fiber via thermal drawing. We then move on to fully characterize the optical and mechanical properties of the fibers and design several fiber-based devices with specific optical effects. More specifically in Chapter 2, we demonstrate the materials selection, innovative fabrication process, and the optical and mechanical characterizations to realize a soft optical wave-guide based on a step-index design. To highlight its optical and mechanical performance, we demonstrate a strain sensing sport gear that integrates this newly developed fiber. In chapter 3, we go one step further in the control over feature size by going about a similar demonstration for a 1D photonic crystal fibers based on all-elastomeric materials, with feature sizes down to sub-100 nm. We show in particular a mechanochromic fiber that can reversibly change color upon stretching. In Chapter 4, we propose a series of other fiber architectures based on our scientific and technological achievements that include a multicore stretchable step-index fiber that form the basis of an advanced demonstrator of a soft fiber with multiple channels and functionalities found in endoscopes. We also present preliminary results on a liquid-core step index fiber, and a stretchable 2D photonic crystal fiber, that pave the way towards highly complex and high-performance soft optical fiber devices.

EPFL2021

Chargement

Advanced Fiber Optics: Concepts and Technology

Luc Thévenaz

Few technologies have had as much impact on society as fiber optics. These tiny hair-sized glass wires have deeply transformed the way we access information, our modes of communication and even the behavior of consumers. Today, optical fibers are omnipresent in modern optical systems, so that a solid background in fiber optics is a prerequisite for any engineer or scientist who has the ambition to become a specialist in the conception and application of systems based on light signals. The aim of this book is to provide advanced students and young researchers with extensive knowledge about optical functions and their novel uses in the toolkit of advanced fiber optics. After an initial chapter summarizing the basic properties and fabrication of optical fibers, each chapter addresses an advanced feature of fiber optics, such as light polarization, amplification and the emission of light by fibers, nonlinear optical interactions, photonic crystal fibers, and generation of a light supercontinuum. Numerous concepts behind novel applications are presented, including the rapidly growing field of distributed sensing, for which natural scattering processes in the fiber material are exploited. The book also addresses the constant search for alternative materials, such the use of polymer optical fibers and the application of chalcogenide and soft glasses, that promise to turn optical fibers into an even more efficient and omnipresent tool for advanced photonics.

EPFL Press, distributed by CRC Press2011

Chargement

Dissipation as a resource in circuit quantum electromechanics

László Dániel Tóth

EPFL2018

EPFL2021