Label-Free, Single-Molecule Detection with Optical Microcavities

Armani, Andrea M.; Kulkarni, Rajan P.; Fraser, Scott E.; Flagan, Richard C.; Vahala, Kerry J.

doi:10.1126/science.1145002

Cited by 1,059 publications

(793 citation statements)

References 51 publications

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“…These narrow line widths make it relatively simple to resolve subtle changes in the resonant frequency, yielding very low limits of detection. 3 In general however to achieve these high Q-factors the electromagnetic energy must be largely confined within a solid structure and thus the extent to which it can interact with the bound molecular targets is limited to a small portion of the evanescent field, negatively impacting device sensitivity.…”

Section: Introductionmentioning

confidence: 99%

A multiplexed optofluidic biomolecular sensor for low mass detection

2009

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Optical techniques have proven to be well suited for in situ biomolecular sensing because they enable high fidelity measurements in aqueous environments, are minimally affected by background solution pH or ionic strength, and facilitate label-free detection. Recently, there has been significant interest in developing new classes of optically resonant biosensors possessing very high quality-factors. This high quality-factor enables them to resolve the presence of very small amounts of bound mass and leads to very low limits of detection. A drawback of these devices is that the majority of the resonant electromagnetic energy is confined within the solid light-guiding structure thus limiting the degree to which it overlaps with the bound matter. This in turn lowers the ultimate device sensitivity, or the change in output signal in response to changes in bound mass. Here we present a novel optofluidic biosensor platform that incorporates a unique one-dimensional photonic crystal resonator array which enables significantly stronger light-matter interaction. We show here how this, coupled with the ability of planar photonic crystals to spatially localize the optical field to mode volumes on the order of a wavelength cubed, enables a limit of detection on the order of 63 ag total bound mass (estimated using a polyelectrolyte growth model) and a device sensitivity an order of magnitude better than similar devices. The multiplexing capabilities of our sensor are demonstrated by the individual and concurrent detection of interleukins 4, 6 and 8 using a sandwich assay.

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Section: Introductionmentioning

confidence: 99%

A multiplexed optofluidic biomolecular sensor for low mass detection

2009

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“…This indirect coupling dramatically modifies the transmission spectra, and is widely used for optical filtering, buffering, switching, and sensing in photonic crystal structures [2][3][4][5] . For micro/nano disk optical cavities, coupling properties are determined by the spatial distance between the disk and the waveguide during the fabrication process.…”

mentioning

confidence: 99%

Indirect coupling between two cavity modes via ferromagnetic resonance

Hyde

Bai

Harder

et al. 2016

Applied Physics Letters

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We experimentally realize indirect coupling between two cavity modes via strong coupling with the ferromagnetic resonance in Yttrium Iron Garnet (YIG). We find that some indirectly coupled modes of our system can have a higher microwave transmission than the individual uncoupled modes. Using a coupled harmonic oscillator model, the influence of the oscillation phase difference between the two cavity modes on the nature of the indirect coupling is revealed. These indirectly coupled microwave modes can be controlled using an external magnetic field or by tuning the cavity height. This work has potential for use in controllable optical devices and information processing technologies.The indirect coupling of cavity modes via a waveguide has been studied theoretically and experimentally for use in optical information processing 1 . This indirect coupling dramatically modifies the transmission spectra, and is widely used for optical filtering, buffering, switching, and sensing in photonic crystal structures 2-5 . For micro/nano disk optical cavities, coupling properties are determined by the spatial distance between the disk and the waveguide during the fabrication process. Therefore, a tunable coupling between indirectly coupled cavity modes is required for potential applications.Recently, strong coupling between a microwave cavity mode and ferromagnetic resonance (FMR) has been realized at room temperature 6-17 . Exchange interactions lock the high density of spins in YIG into a macro-spin state, leading to strong coupling with a cavity mode which can be adjusted using an external magnetic field. Potential applications of this form of strong coupling are currently being explored. For example, indirect coupling between the FMR in two YIG spheres has produced dark magnon modes with potential uses in information storage technologies 18 , and the FMR of YIG has been indirectly coupled with a qubit through a microwave cavity mode 19 . Instead of using a microwave cavity mode to build a bridge between two oscillators, we have used the FMR in YIG to produce indirect coupling between two cavity modes.In this work, we present two cavity modes which indirectly couple via their strong coupling with the FMR in YIG at room temperature. The two cavity modes are labelled h ω1 (ω) and h ω2 (ω) respectively, and are independent of each other when there is no direct coupling between them. Here ω 1 and ω 2 are the uncoupled resonance frequencies of each cavity mode and ω is the input microwave frequency. The two cavity modes can be indirectly coupled with each other when they both individually interact with the FMR in YIG and this indirect coupling can be controlled using an external magnetic field. We found that the microwave transmission properties change dramatically for the coupled modes as the external field is tuned. Our experimental results,

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“…Optical sensors based on ultrahigh quality factor whispering-gallery microcavities have recently been demonstrated to be able to detect label-free single molecule binding events [36 ]. This potential for ultra-high sensitivity makes microcavities interesting candidates where sensitivity is the most important parameter [37].…”

Section: Nanowires Optical Microcavities Nanomechanical Resonatorsmentioning

confidence: 99%

Next generation microfluidic platforms for high-throughput protein biochemistry

Maerkl

2011

Current Opinion in Biotechnology

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Label-Free, Single-Molecule Detection with Optical Microcavities

Cited by 1,059 publications

References 51 publications

A multiplexed optofluidic biomolecular sensor for low mass detection

A multiplexed optofluidic biomolecular sensor for low mass detection

Indirect coupling between two cavity modes via ferromagnetic resonance

Next generation microfluidic platforms for high-throughput protein biochemistry

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