During the last few years cavity-optomechanics has emerged as a new field of research. This highly interdisciplinary field studies the interaction between micro and nano mechanical systems and light. Possible applications range from novel high-bandwidth mechanical sensing devices through the generation of squeezed optical or mechanical states to even tests of quantum theory itself. This is one of the first books in this relatively young field. It is aimed at scientists, engineers and students who want to obtain a concise introduction to the state of the art in the field of cavity optomechanics. It is valuable to researchers in nano science, quantum optics, quantum information, gravitational wave detection and other cutting edge fields. Possible applications include biological sensing, frequency comb applications, silicon photonics etc. The technical content will be accessible to those who have familiarity with basic undergraduate physics.

This thesis presents experimental research on the interaction between the optical field and the mechanical oscillator in whispering-gallery mode microcavities. It demonstrates how optomechanical interactions in a microresonator can be used to achieve non-magnetic non-reciprocity and develop all-optically controlled non-reciprocal multifunctional photonic devices. The thesis also discusses the interaction between the travelling optical and mechanical whispering-gallery modes, paving the way for non-reciprocal light storage as a coherent, circulating acoustic wave with a lifetime of up to tens of microseconds. Lastly, the thesis presents a high-frequency phase-sensitive heterodyne vibrometer, operating up to 10 GHz, which can be used for the high-resolution, non-invasive mapping of the vibration patterns of acoustic devices. The results presented here show that optomechanical devices hold great potential in the field of information processing.

Written by leading experimentalist Warwick P. Bowen and prominent theoretician Gerard J. Milburn, Quantum Optomechanics discusses modern developments in this novel field from experimental and theoretical standpoints. The authors share their insight on a range of important topics, including optomechanical cooling and entanglement; quantum limits on

Superfluid helium is a quantum liquid that exhibits a range of counter-intuitive phenomena such as frictionless flow. Quantized vortices are a particularly important feature of superfluid helium, and all superfluids, characterized by a circulation that can only take prescribed integer values. However, the strong interactions between atoms in superfluid helium prohibit quantitative theory of vortex behaviour. Experiments have similarly not been able to observe coherent vortex dynamics. This thesis resolves this challenge, bringing microphotonic techniques to bear on two-dimensional superfluid helium, observing coherent vortex dynamics for the first time, and achieving this on a silicon chip. This represents a major scientific contribution, as it opens the door not only to providing a better understanding of this esoteric quantum state of matter, but also to building new quantum technologies based upon it, and to understanding the dynamics of astrophysical superfluids such as those thought to exist in the core of neutron stars.

A mechanical oscillator coupled to the optical field in a cavity is a typical cavity optomechanical system. In our textbook, we prepare to introduce the quantum optical properties of optomechanical system, i.e. linear and nonlinear effects. Some quantum optical devices based on optomechanical system are also presented in the monograph, such as the Kerr modulator, quantum optical transistor, optomechanical mass sensor, and so on. But most importantly, we extend the idea of typical optomechanical system to coupled mechanical resonator system and demonstrate that the combined two-level structure and resonator system can serve as a generalized optomechanical system. The quantum optical properties, which exist in typical system, are also presented in the combined two-level structure and resonator system.

This book fully covers all aspects -- historical, theoretical, and experimental -- of the fields of quantum optomechanics and nanomechanics. These are essential parts of modern physics research, and relate to gravitational-wave detection (the subject of the Physics Nobel Prize 2017), and quantum information.

Quantum effects in macroscopic systems have long been a fascination for researchers. Over the past decade mechanical oscillators have emerged as a leading system of choice for many such experiments. The work reported in this thesis investigates the effects of the radiation-pressure force of light on macroscopic mechanical structures. The basic system studied is a mechanical oscillator that is highly reflective and part of an optical resonator. It interacts with the optical cavity mode via the radiation-pressure force. Both the dynamics of the mechanical oscillation and the properties of the light field are modified through this interaction. The experiments use quantum optical tools (such as homodyning and down-conversion) with the goal of ultimately showing quantum behavior of the mechanical center of mass motion. Of particular value are the detailed descriptions of several novel experiments that pave the way towards this goal and are already shaping the field of quantum optomechanics, in particular optomechanical laser cooling and strong optomechanical coupling.