The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Stephen Arnold - One of the best experts on this subject based on the ideXlab platform.
-
detection of protein orientation on the silica microsphere surface using transverse electric transverse magnetic Whispering Gallery Modes
Biophysical Journal, 2007Co-Authors: Mayumi Noto, Iwao Teraoka, D Keng, Stephen ArnoldAbstract:The state of adsorbed protein molecules can be examined by comparing the shifts in a narrow line resonance wavelength of transverse electric (TE) and transverse magnetic (TM) Whispering Gallery Modes (WGM) when the molecules adsorb onto a transparent microsphere that houses WGM. In adsorption of bovine serum albumin (BSA) onto an aminopropyl-modified silica microsphere, the TM/TE shift ratio indicated highly anisotropic polarizability of BSA in the direction normal to the surface, most likely ascribed to anchoring the heart-shaped protein molecule by one of its tips. The polarization-dependent resonance shift was confirmed when the surrounding refractive index was uniformly changed by adding salt, which would simulate adsorption of large objects.
-
theory of resonance shifts in te and tm Whispering Gallery Modes by nonradial perturbations for sensing applications
Journal of The Optical Society of America B-optical Physics, 2006Co-Authors: Iwao Teraoka, Stephen ArnoldAbstract:A perturbation theory is presented for the frequency shift of highly resonant photonic Whispering Gallery Modes in a transparent sphere. Using a vector wave equation, we derive a general formula for the shifts in TE and TM polarization by adsorption of another dielectric medium. The adsorbed medium can have an arbitrary shape and refractive-index profile. The formula is applied to adsorption of a thin layer and deposition of a small spherical particle, many such particles, and thin cylindrical particles on the resonator surface. We found that the ratio of the TM mode shift to the TE mode shift is sensitive to the shape of the adsorbates and their orientation. Calculation results are discussed in terms of a dipolar field.
-
Temperature Measurements Using a Microoptical Sensor Based on Whispering Gallery Modes
AIAA Journal, 2006Co-Authors: Guoming Guan, Stephen Arnold, Volkan ÖtügenAbstract:Temperature measurements were made using a novel microoptical sensor based on dielectric microspheres that are excited by coupling light from optical fibers. The technique exploits the morphology-dependent shifts in resonant frequencies that are commonly referred to as the Whispering Gallery Modes. A change in the temperature of the microsphere leads to a change in both the size and the index of refraction of the sphere which results in a shift of the resonant frequency. By monitoring this shift, the temperature of the environment surrounding the sphere can be determined. The Whispering Gallery mode shifts are observed by scanning a tunable diode laser that is coupled into the optical fiber on one end and monitoring the transmission spectrum by a photodiode on the other. When the microsphere is in contact with a bare section of the fiber, the optical Modes are observed as dips in the intensity of the light transmitted through the fiber. Temperature measurements were made in both air and water using this novel technique. Measurements by the microoptical sensor were compared to those by thermocouples with good agreement between the two sets of results.
-
shift of Whispering Gallery Modes in microspheres by protein adsorption
Optics Letters, 2003Co-Authors: Stephen Arnold, M Khoshsima, Iwao Teraoka, Stephen Holler, Frank VollmerAbstract:Biosensors based on the shift of Whispering-Gallery Modes in microspheres accompanying protein adsorption are described by use of a perturbation theory. For random spatial adsorption, theory predicts that the shift should be inversely proportional to micorsphere radius R and proportional to protein surface density and excess polarizability. Measurements are found to be consistent with the theory, and the correspondence enables the average surface area occupied by a single protein to be estimated. These results are consistent with crystallographic data for bovine serum albumin. The theoretical shift for adsorption of a single protein is found to be extremely sensitive to the target region, with adsorption in the most sensitive region varying as 1R 52 . Specific parameters for single protein or virus particle detection are predicted. © 2003 Optical
Vladimir S Ilchenko - One of the best experts on this subject based on the ideXlab platform.
-
low threshold parametric nonlinear optics with quasi phase matched Whispering Gallery Modes
Journal of The Optical Society of America B-optical Physics, 2003Co-Authors: Vladimir S Ilchenko, Anatoliy A Savchenkov, Andrey B Matsko, Lute MalekiAbstract:We propose to fabricate a toroidal dielectric cavity from a periodically poled χ(2) nonlinear material (e.g., LiNbO3) to achieve efficient interaction among high-Q Whispering-Gallery Modes. We show that the periodic poling allows for suppression of both material and cavity dispersion. Such a cavity might be a basic element of a family of efficient nonlinear devices operating at a broad range of optical wavelengths.
-
dispersion compensation in Whispering Gallery Modes
Journal of The Optical Society of America A-optics Image Science and Vision, 2003Co-Authors: Vladimir S Ilchenko, Anatoliy A Savchenkov, Andrey B Matsko, Lute MalekiAbstract:We show that manipulation by a spatial profile of the refractive index of a circularly symmetric dielectric cavity results in a novel way of fine tuning frequency separations as well as spatial localizations of high-Q Whispering-Gallery Modes excited in the cavity. The method permits dispersion compensation in the Modes (spectrum equalization), diminishes the quality-factor limitation by surface roughness and contamination, and allows critical coupling to ultra-high-Q Modes without maintaining an air gap with evanescent couplers.
-
microtorus a high finesse microcavity with Whispering Gallery Modes
Optics Letters, 2001Co-Authors: Vladimir S Ilchenko, M L Gorodetsky, Xiaotian Steve Yao, Lute MalekiAbstract:We demonstrate a 165-mu;m oblate spheroidal microcavity with a free spectral range of 383.7 GHz (3.06 nm), a resonance bandwidth of 23 MHz (quality factor Q approximately 10(7)) at 1550 nm, and finesse F>/=10(4) . The highly oblate spheroidal dielectric microcavity combines a very high Q factor, typical of microspheres, with a vastly reduced number of excited Whispering-Gallery Modes (by 2 orders of magnitude). The very large free spectral range in this novel microcavity-a few hundred gigahertz instead of a few gigahertz as in typical microspheres-is desirable for applications in spectral analysis, narrow-linewidth optical and rf oscillators, and cavity QED.
-
frequency tuning of the Whispering Gallery Modes of silica microspheres for cavity quantum electrodynamics and spectroscopy
Optics Letters, 2001Co-Authors: Wolf Von Klitzing, Vladimir S Ilchenko, J. Hare, Romain Long, Valerie LefevreseguinAbstract:We have tuned the Whispering-Gallery Modes of a fused-silica microresonator over nearly 1 nm at 800 nm, i.e., over half a free spectral range, or 106 linewidths of the resonator. This result has been achieved by use of a new method based on the stretching of a two-stem microsphere. We describe devices that will permit new cavity QED experiments with this high-Q optical resonator when it is desirable to optimize its coupling to emitters with given transition frequencies. The demonstrated tuning capability is compatible with both UHV and low-temperature operation, which should be useful for future experiments with laser-cooled atoms or single quantum dots.
-
tunable Whispering Gallery Modes for spectroscopy and cqed experiments
arXiv: Quantum Physics, 2000Co-Authors: Wolf Von Klitzing, Vladimir S Ilchenko, J. Hare, Romain Long, Valerie LefevreseguinAbstract:We have tuned the Whispering Gallery Modes of a fused silica micro- resonator over nearly 1 nm at 800 nm, i.e.over half of a free spectral range or the equivalent of 10^6 linewidths of the resonator.This has been achieved by a new method based on the stretching of a two-stem microsphere.The devices described below will permit new Cavity-QED experiments with this ultra high .nesse optical resonator when it is desirable to optimise its coupling to emitters with given transition frequencies. The tuning capability demonstrated is compatible with both UHV and low temperature operation which should be useful for future experiments with laser cooled atoms or single quantum dots.A general overview of the current state of the art in microspheres is given as well as a more general introduction.
Lute Maleki - One of the best experts on this subject based on the ideXlab platform.
-
low threshold parametric nonlinear optics with quasi phase matched Whispering Gallery Modes
Journal of The Optical Society of America B-optical Physics, 2003Co-Authors: Vladimir S Ilchenko, Anatoliy A Savchenkov, Andrey B Matsko, Lute MalekiAbstract:We propose to fabricate a toroidal dielectric cavity from a periodically poled χ(2) nonlinear material (e.g., LiNbO3) to achieve efficient interaction among high-Q Whispering-Gallery Modes. We show that the periodic poling allows for suppression of both material and cavity dispersion. Such a cavity might be a basic element of a family of efficient nonlinear devices operating at a broad range of optical wavelengths.
-
dispersion compensation in Whispering Gallery Modes
Journal of The Optical Society of America A-optics Image Science and Vision, 2003Co-Authors: Vladimir S Ilchenko, Anatoliy A Savchenkov, Andrey B Matsko, Lute MalekiAbstract:We show that manipulation by a spatial profile of the refractive index of a circularly symmetric dielectric cavity results in a novel way of fine tuning frequency separations as well as spatial localizations of high-Q Whispering-Gallery Modes excited in the cavity. The method permits dispersion compensation in the Modes (spectrum equalization), diminishes the quality-factor limitation by surface roughness and contamination, and allows critical coupling to ultra-high-Q Modes without maintaining an air gap with evanescent couplers.
-
microtorus a high finesse microcavity with Whispering Gallery Modes
Optics Letters, 2001Co-Authors: Vladimir S Ilchenko, M L Gorodetsky, Xiaotian Steve Yao, Lute MalekiAbstract:We demonstrate a 165-mu;m oblate spheroidal microcavity with a free spectral range of 383.7 GHz (3.06 nm), a resonance bandwidth of 23 MHz (quality factor Q approximately 10(7)) at 1550 nm, and finesse F>/=10(4) . The highly oblate spheroidal dielectric microcavity combines a very high Q factor, typical of microspheres, with a vastly reduced number of excited Whispering-Gallery Modes (by 2 orders of magnitude). The very large free spectral range in this novel microcavity-a few hundred gigahertz instead of a few gigahertz as in typical microspheres-is desirable for applications in spectral analysis, narrow-linewidth optical and rf oscillators, and cavity QED.
-
pigtailing the high q microsphere cavity a simple fiber coupler for optical Whispering Gallery Modes
Optics Letters, 1999Co-Authors: Vladimir S Ilchenko, Steve X Yao, Lute MalekiAbstract:We demonstrate a simple method for efficient coupling of standard single-mode optical fibers to a high-Q optical microsphere cavity. Phase-matched excitation of Whispering-Gallery Modes is provided by an angle-polished fiber tip in which the core-guided wave undergoes total internal reflection. In the experimental setup, which included a microsphere with both an input and an output coupler, the total fiber-to-fiber transmission at resonance reached 23% (total insertion loss, 6.3??dB), with loaded quality factor Q?3×107 and unloaded Q?1.2×108 at 1550??nm. A simple pigtailing method for microspheres permits their wider use in fiber optics and photonics devices.
-
pigtailing the high q microsphere cavity a simple fiber coupler for optical Whispering Gallery Modes
Optics Letters, 1999Co-Authors: Vladimir S Ilchenko, Steve X Yao, Lute MalekiAbstract:We demonstrate a simple method for efficient coupling of standard single-mode optical fibers to a high- Q optical microsphere cavity. Phase-matched excitation of Whispering-Gallery Modes is provided by an angle-polished fiber tip in which the core-guided wave undergoes total internal reflection. In the experimental setup, which included a microsphere with both an input and an output coupler, the total fiber-to-fiber transmission at resonance reached 23% (total insertion loss, 6.3 dB), with loaded quality factor Q> or =3 x 10(7) and unloaded Q approximately 1.2 x 10(8) at 1550 nm. A simple pigtailing method for microspheres permits their wider use in fiber optics and photonics devices.
Andrew Wing On Poon - One of the best experts on this subject based on the ideXlab platform.
-
optical manipulation of microparticles using Whispering Gallery Modes in a silicon nitride microdisk resonator
Optics Letters, 2011Co-Authors: Hong Cai, Andrew Wing On PoonAbstract:We demonstrate optical manipulation of 1 μm sized polystyrene microparticles on silicon nitride microdisk resonator devices using Whispering-Gallery Modes in an integrated optofluidic chip. We demonstrate multiple trapping tracks and extended trapping ranges within single wavelengths through exciting high-order Modes. We observe various sets of trapping tracks and ranges through exciting various resonance Modes. We switch particle traveling tracks by tuning the laser wavelength to various wavelengths. We also observe microparticles assembling along the trapping tracks.
-
optical manipulation of microparticles using Whispering Gallery Modes in a silicon nitride microdisk resonator
Conference on Lasers and Electro-Optics, 2011Co-Authors: Hong Cai, Andrew Wing On PoonAbstract:We demonstrate optical manipulation of microparticles on a silicon nitride microdisk resonator in an optofluidic chip. We observe three trapping channels at 1.3, 2.3 and 3.0 μm from the microdisk rim upon different Whispering-Gallery Modes.
Sunghwan Rim - One of the best experts on this subject based on the ideXlab platform.
-
Whispering Gallery Modes in triple microdisks of triangular configurations
Journal of The Optical Society of America B-optical Physics, 2020Co-Authors: Jung-wan Ryu, Sunghwan RimAbstract:We study Whispering Gallery Modes in triple microdisks of equilateral and isosceles triangular configurations. The characteristic properties of resonant Modes in three microdisks on the vertices of an equilateral triangle are explained by the discrete rotational symmetry of the triangle. The avoided crossings of resonant Modes in three microdisks on the vertices of an isosceles triangle also are studied in terms of a combination of single and coupled microdisks. In addition, we propose matrix models that well explain the resonant Modes in triple microdisks.
