&lt;title&gt;High-Q whispering-gallery mode sensor in liquids&lt;/title&gt;

Nadeau, Jay; Ilchenko, Vladimir S.; Kossakovski, Dmitri; Bearman, Gregory H.; Maleki, Lute

doi:10.1117/12.469488

Cited by 59 publications

(33 citation statements)

References 10 publications

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“…Reducing the diameter of the resonator has one substantial drawback; namely that the resolution of the sensor, which is related to the Q-factor of the resonator, decreases significantly for small resonators. Large resonators, ranging from 50 to 300μm in diameter, typically exhibit a Qfactor up to several millions [1,3,16], whereas smaller resonators (below 20μm in diameter) reported in literature have been limited to a Q-factor of around 10 3 in liquids [8,13]. One approach for improving the Q-factor of small resonators is the use of active resonators [6,7,17] which contain a gain medium (unlike passive resonators [1][2][3]) and can induce lasing of the WGMs.…”

Section: Introductionmentioning

confidence: 99%

Enhancing the radiation efficiency of dye doped whispering gallery mode microresonators

François¹,

Rowland²,

Afshar³

et al. 2013

Opt. Express

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Section: Introductionmentioning

confidence: 99%

Enhancing the radiation efficiency of dye doped whispering gallery mode microresonators

François¹,

Rowland²,

Afshar³

et al. 2013

Opt. Express

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“…16 Also, optical biosensors can be extremely sensitive (nanomolar concentrations or less), nondestructive to the sample, and the transduction processes in optical biosensors generally takes place at a surface and can be tailored to sense almost any kind of molecule, chemical and biological. 17 Optical sensing can be performed using ring resonators, 18 confocal microscopy, 7 prism couplers, 19 spherical cavities, 20 and fiber-optic waveguides. 21 In ring resonators, spherical cavities, and fiber-optics waveguides, the light is coupled through the waveguides, and an evanescent field extends beyond the waveguide surface by ≈100 nm.…”

Section: Introductionmentioning

confidence: 99%

Photonic detection and characterization of DNA using sapphire microspheres

et al. 2014

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Abstract. A microcavity-based deoxyribonucleic acid (DNA) optical biosensor is demonstrated for the first time using synthetic sapphire for the optical cavity. Transmitted and elastic scattering intensity at 1510 nm are analyzed from a sapphire microsphere (radius 500 μm, refractive index 1.77) on an optical fiber half coupler. The 0.43 nm angular mode spacing of the resonances correlates well with the optical size of the sapphire sphere. Probe DNA consisting of a 36-mer fragment was covalently immobilized on a sapphire microsphere and hybridized with a 29-mer target DNA. Whispering gallery modes (WGMs) were monitored before the sapphire was functionalized with DNA and after it was functionalized with single-stranded DNA (ssDNA) and double-stranded DNA (dsDNA). The shift in WGMs from the surface modification with DNA was measured and correlated well with the estimated thickness of the add-on DNA layer. It is shown that ssDNA is more uniformly oriented on the sapphire surface than dsDNA. In addition, it is shown that functionalization of the sapphire spherical surface with DNA does not affect the quality factor (Q ≈ 10 4 ) of the sapphire microspheres. The use of sapphire is especially interesting because this material is chemically resilient, biocompatible, and widely used for medical implants.

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“…Our results therefore suggest that the Q factor has a much stronger influence on the lasing threshold than initially anticipated although further investigations could be pursued beyond the work reported here to understand fully the dependency of the lasing threshold on the Q factor. Nevertheless, as measurement of the Q factor has been used in previous work on WGMs to characterize changes of surrounding refractive index and biomolecular binding onto high Q factor resonator [25] , one might appreciate that measuring the lasing threshold might be an interesting alternative to the standard resonance wavelength characterization, especially if the dependency of the lasing threshold varies as a power function of the Q factor.…”

Section: Lasing Whispering-gallery Mode Microsphere In Watermentioning

confidence: 99%