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

Microcavity physics and design will be reviewed. Following an overview of applications in quantum optics, communications and biosensing, recent advances in ultra-high-Q research will be presented.

Optical microcavities

We demonstrate microfabrication of ultra-high-Q microcavities on a chip, exhibiting a novel toroid-shaped geometry. The cavities possess Q-factors in excess of 100 million which constitutes an improvement close to 4 orders-of-magnitude in Q compared to previous work [B. Gayral, et al., 1999].

Ultra-high-Q toroid microcavities on a chip

An overview of analog microwave photonics will be presented. The performance requirements for externally-modulated analog microwave photonic links will be reviewed with specific emphasis placed on modulator efficiency, laser noise, detected photocurrent, and link linearity.

http://ieeexplore.ieee.org/iel5/6387506/6403300/06403360.pdf

Microwave photonics

The present invention provides nanometer-sized diameter silica fibers that exhibit high diameter uniformity and surface smoothness. The silica fibers can have diameters in a range of a about 20 nm to about 1000 nm. An exemplary method according to one embodiment of the invention for generating such fibers utilizes a two-step process in which in an initial step a micrometer sized diameter silica preform fiber is generated, and in a second step, the silica preform is drawn while coupled to a support element to form a nanometer sized diameter silica fiber. The portion of the support element to which the preform is coupled is maintained at a temperature suitable for drawing the nansized fiber, and is preferably controlled to exhibit a temporally stable temperature profile.

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Subwavelength-diameter silica wires for low-loss optical waveguiding

We present the observation of critical coupling in a high-Q fused-silica microsphere whispering-gallery mode resonator coupled to a fiber taper Extremely efficient and controlled power transfer to high-Q (∼10^7) resonators has been demonstrated Off-resonance scattering loss was measured to be less than 03% On-resonance extinction in transmitted optical power through the fiber coupler was measured as high as 26 dB at the critical coupling point This result opens up a range of new applications in fields as diverse as near-field sensing and quantum optics

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Observation of critical coupling in a fiber taper to a silica-microsphere whispering-gallery mode system

We demonstrate a 1.5-mm-wavelength fiber laser formed by placement of glass microsphere resonators along a fiber taper. The fiber taper serves the dual purpose of transporting optical pump power into the spheres and extracting the resulting laser emission. A highly doped erbium:ytterbium phosphate glass was used to form microsphere resonant cavities with large gain at 1.5 mm. Laser threshold pump powers of 60 mW and fiber-coupled output powers as high as 3 mW with single-mode operation were obtained. A bisphere laser system consisting of two microspheres attached to a single fiber taper is also demonstrated. © 2000 Optical Society of America

/pdf/fiber-coupled-microsphere-laser-5fkk061p9z.pdf

Fiber-coupled microsphere laser.

An all-optical passive four-port system including a fused silica microsphere and two tapered fibers is proposed and demonstrated for the application as a channel adding-dropping device. It is shown that channels can be selectively exchanged between two fibers by coupling to a whispering gallery mode resonance in the microsphere. Finesse in excess of 11150 is measured for the loaded whispering gallery modes.

/pdf/fiber-optic-add-drop-device-based-on-a-silica-microsphere-jlrh4slmrz.pdf

Fiber-optic add-drop device based on a silica microsphere-whispering gallery mode system

We report that greater than 99.8% optical power transfer to whispering-gallery modes was achieved in fused-silica microspheres by use of a dual-tapered-fiber coupling method. The intrinsic cavity loss and the taper-to-sphere coupling coefficient are inferred from the experimental data. It is shown that the low intrinsic cavity loss and the symmetrical dual-coupling structure are crucial for obtaining the high coupling efficiency.

/pdf/highly-efficient-optical-power-transfer-to-whispering-54umqvk4wj.pdf

Highly efficient optical power transfer to whispering-gallery modes by use of a symmetrical dual-coupling configuration.

The present invention is a micro-cavity laser and methods related thereto. In the preferred embodiments, the micro-cavity laser comprises a laser pump signal in a fiber waveguide which is optically coupled to a micro-cavity resonator through a fiber taper. The micro-resonator includes a gain medium necessary for lasing action. The lasing frequency can be determined based upon the gain medium, the micro-cavity structure, as well as frequency selective elements such as gratings incorporated into the micro-cavity. The tapered fiber waveguide permits the micro-cavity laser to operate without a break in the fiber waveguide. In the preferred embodiments, the micro-cavity resonator is constructed from a doped silica or a semiconductor material. The present invention provides a compact laser with improved emissions and coupling efficiencies. Alternative configurations include multiple micro-cavities on a single fiber waveguide and/or utilizing multiple waveguides attached to one or more micro-cavity resonators. The laser can be made to operate in a continuous-wave as opposed to self-pulsing mode.

Ming Cai

Papers

Observation of critical coupling in a fiber taper to a silica-microsphere whispering-gallery mode system

Fiber-coupled microsphere laser.

Fiber-optic add-drop device based on a silica microsphere-whispering gallery mode system

Highly efficient optical power transfer to whispering-gallery modes by use of a symmetrical dual-coupling configuration.

Micro-cavity laser