다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

[신간의 별자리x] 우리/미술, 그리고 ‘슬픔의 박물관’

We review the field of cavity optomechanics, which explores the interaction between electromagnetic radiation and nano- or micromechanical motion This review covers the basics of optical cavities and mechanical resonators, their mutual optomechanical interaction mediated by the radiation pressure force, the large variety of experimental systems which exhibit this interaction, optical measurements of mechanical motion, dynamical backaction amplification and cooling, nonlinear dynamics, multimode optomechanics, and proposals for future cavity quantum optomechanics experiments In addition, we describe the perspectives for fundamental quantum physics and for possible applications of optomechanical devices

Cavity Optomechanics

It is now shown that coupled optical microcavities bear all the hallmarks of parity–time symmetry; that is, the system’s dynamics are unchanged by both time-reversal and mirror transformations. The resonant nature of microcavities results in unusual effects not seen in previous photonic analogues of parity–time-symmetric systems: for example, light travelling in one direction is resonantly enhanced but there are no resonance peaks going the other way.

Parity–time-symmetric whispering-gallery microcavities

In recent years, notions drawn from non-Hermitian physics and parity–time (PT) symmetry have attracted considerable attention. In particular, the realization that the interplay between gain and loss can lead to entirely new and unexpected features has initiated an intense research effort to explore non-Hermitian systems both theoretically and experimentally. Here we review recent progress in this emerging field, and provide an outlook to future directions and developments. This Review Article outlines the exploration of the interplay between parity–time symmetry and non-Hermitian physics in optics, plasmonics and optomechanics.

Non-Hermitian physics and PT symmetry

Embodiments of the invention provide Raman spectroscopy methods and devices that exploit high quality factor (Q) resonators to enhance Raman signal by several orders of magnitude over the signal typically expected for Raman methods. Embodiments typically include one or more resonators, typically microtoroid microresonators. Embodiments also take advantage of Rayleigh scattering using these microresonators. Embodiments may be particularly useful for non-labeled nanoparticle sensing.

Resonator enhanced raman spectroscopy

Complex wave interference suppresses nonlinearities that destabilize beams For many laser applications, beam stability is critical, but chaotic lasing dynamics can create spatiotemporal instabilities. A long-standing problem in high-power semiconductor lasers (1, 2) is that instabilities can arise from deterministic and random effects that control the complex interactions between the radiation field and matter. The conventional approach to suppress instabilities is to reduce the level of complexity of the system. On page 1225 of this issue, Bittner et al. (3) now report a counterintuitive method that introduces an additional layer of complexity, chaotic ray dynamics, to mitigate chaos in lasing dynamics—a strategy similar to “fighting fire with fire.”

https://science.sciencemag.org/content/sci/361/6408/1201.full.pdf

Fighting chaos with chaos in lasers

A method for performing Raman spectroscopic analysis of micro-particles adhered to a tapered optical fiber as they interact with the taper-guided evanescent pump wave is explored as a chemically selective, label-free taper-particle sensing technique.

Fiber taper based Raman spectroscopic sensing

Quantum input-output theory plays a very important role for analyzing the dynamics of quantum systems, especially large-scale quantum networks. As an extension of the input-output formalism of Gardiner and Collet, we develop a new approach based on the quantum version of the Volterra series which can be used to analyze nonlinear quantum input-output dynamics. By this approach, we can ignore the internal dynamics of the quantum input-output system and represent the system dynamics by a series of kernel functions. This approach has the great advantage of modelling weak-nonlinear quantum networks. In our approach, the number of parameters, represented by the kernel functions, used to describe the input-output response of a weak-nonlinear quantum network, increases linearly with the scale of the quantum network, not exponentially as usual. Additionally, our approach can be used to formulate the quantum network with both nonlinear and nonconservative components, e.g., quantum amplifiers, which cannot be modelled by the existing methods, such as the Hudson-Parthasarathy model and the quantum transfer function model. We apply our general method to several examples, including Kerr cavities, optomechanical transducers, and a particular coherent feedback system with a nonlinear component and a quantum amplifier in the feedback loop. This approach provides a powerful way to the modelling and control of nonlinear quantum networks.

Nonlinear quantum input-output analysis using Volterra series

We report real time detection of individual nanoparticles down to R=20 nm using a high-Q whispering gallery mode (WGM) microresonator. The detection is based on resonance enhanced particle induced reflection and does not require monitoring resonance spectra.

Lan Yang

Papers

Resonator enhanced raman spectroscopy

Fighting chaos with chaos in lasers

Fiber taper based Raman spectroscopic sensing

Nonlinear quantum input-output analysis using Volterra series

Reflection detection of nanoparticles using whispering gallery microresonators