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

Photonic crystal fibers guide light by corralling it within a periodic array of microscopic air holes that run along the entire fiber length Largely through their ability to overcome the limitations of conventional fiber optics—for example, by permitting low-loss guidance of light in a hollow core—these fibers are proving to have a multitude of important technological and scientific applications spanning many disciplines The result has been a renaissance of interest in optical fibers and their uses

https://science.sciencemag.org/content/sci/299/5605/358.full.pdf

Photonic crystal fibers

A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

We review the recent developments in the area of optical fiber grating sensors, including quasi-distributed strain sensing using Bragg gratings, systems based on chirped gratings, intragrating sensing concepts, long period-based grating sensors, fiber grating laser-based systems, and interferometric sensor systems based on grating reflectors.

Fiber grating sensors

A topical review of numerical and experimental studies of supercontinuum generation in photonic crystal fiber is presented over the full range of experimentally reported parameters, from the femtosecond to the continuous-wave regime. Results from numerical simulations are used to discuss the temporal and spectral characteristics of the supercontinuum, and to interpret the physics of the underlying spectral broadening processes. Particular attention is given to the case of supercontinuum generation seeded by femtosecond pulses in the anomalous group velocity dispersion regime of photonic crystal fiber, where the processes of soliton fission, stimulated Raman scattering, and dispersive wave generation are reviewed in detail. The corresponding intensity and phase stability properties of the supercontinuum spectra generated under different conditions are also discussed.

Supercontinuum generation in photonic crystal fiber

We demonstrate broadband, frequency-tunable, phase-locked terahertz (THz) generation and detection based on difference frequency mixing of temporally and spectrally structured near-infrared (NIR) pulses. The pulses are prepared in a gas-filled hollow-core photonic crystal fiber (HC-PCF), whose linear and nonlinear optical properties can be adjusted by tuning the gas pressure. This permits optimization of both the spectral broadening of the pulses due to self-phase modulation (SPM) and the generated THz spectrum. The properties of the prepared pulses, measured at several different argon gas pressures, agree well with the results of numerical modeling. Using these pulses, we perform difference frequency generation in a standard time-resolved THz scheme. As the argon pressure is gradually increased from 0 to 10 bar, the NIR pulses spectrally broaden from 3.5 to 8.7 THz, while the measured THz bandwidth increases correspondingly from 2.3 to 4.5 THz. At 10 bar, the THz spectrum extends to 6 THz, limited only by the spectral bandwidth of our time-resolved detection scheme. Interestingly, SPM in the HC-PCF produces asymmetric spectral broadening that may be used to enhance the generation of selected THz frequencies. This scheme, based on a HC-PCF pulse shaper, holds great promise for broadband time-domain spectroscopy in the THz, enabling the use of compact and stable ultrafast laser sources with relatively narrow linewidths (<4 THz).

/pdf/broadband-and-tunable-time-resolved-thz-system-using-argon-2ls0n8bufd.pdf

Broadband and tunable time-resolved THz system using argon-filled hollow-core photonic crystal fiber

Publisher Summary Photonic crystal fibers (PCFs) have a periodic transverse microstructure and emerged as practical low-loss waveguides. They have extended the range of possibilities in optical fibers, both by improving well-established properties and by introducing new features such as low-loss guidance in a hollow core. This chapter provides an introduction to various types of PCFs along with their established or emerging applications. Applications of photonic crystal fibers include lasers, amplifiers, dispersion compensators, and nonlinear processing. Photonic crystal fiber structures are currently produced in many laboratories worldwide using a variety of different techniques. An important stage is to produce a There are many ways to do this, including stacking of capillaries and rods extrusion, sol-gel casting, injection molding, and drilling. The materials used range from silica to compound glasses, chalcogenide glasses, and polymers.

Photonic crystal fibers: Basics and applications

We describe the fabrication and characterization of a free-standing silica glass membrane waveguide formed using fiber fabrication processes. The membrane has a thickness of 0.6??m and a width of 60??m and is many meters long. The optical attenuation is measured as 0.4?dB?m. Such attenuation outperforms that of conventional planar waveguides by several orders of magnitude.

Linear and nonlinear guidance in an ultralow loss planar glass membrane.

Tunable acousto-optic spectral filters based on null couplers have been improved by making the coupler more uniform A new double-pass arrangement further narrows the bandwidth, reduces the sidelobes to -20 dB and doubles the frequency shift

All-fibre acousto-optic tunable filter based on a null coupler

Photonic crystal fibers (PCFs) have been receiving increasing attention over the past few years. They are single material fibers that use an array of air holes in the cladding to confine light to a core, instead of the more usual refractive index step within the solid material of a conventional fiber. As PCFs become more well-understood mainstream structures, the need arises to develop techniques to process them post-fabrication to form all-fiber devices. We have chosen to study heat-treatment processes analogous to the tapering of conventional fibers, except that in PCFs there is a second degree of freedom to exploit. Not only can the fiber be stretched to locally reduce its cross-sectional area, the air holes can be changed in size by heating alone under the effect of surface tension.

Philip St. J. Russell

Papers

Broadband and tunable time-resolved THz system using argon-filled hollow-core photonic crystal fiber

Photonic crystal fibers: Basics and applications

Linear and nonlinear guidance in an ultralow loss planar glass membrane.

All-fibre acousto-optic tunable filter based on a null coupler

Photonic crystal fiber devices