Detecting single viruses and nanoparticles using whispering gallery microlasers.

By Lina He, Ş. Özdemir, Jiangang Zhu, Woosung Kim, Lan Yang. Nature Nanotechnology, 2011

640 citations recorded by the source corpus.

There is a strong demand for portable systems that can detect and characterize individual pathogens and other nanoscale objects without the use of labels, for applications in human health, homeland security, environmental monitoring and diagnostics. However, most nanoscale objects of interest have low polarizabilities due to their small size and low refractive index contrast with the surrounding medium. This leads to weak light-matter interactions, and thus makes the label-free detection of single nanoparticles very difficult. Micro- and nano-photonic devices have emerged as highly sensitive platforms for such applications, because the combination of high quality factor Q and small mode volume V leads to significantly enhanced light-matter interactions. For example, whispering gallery mode microresonators have been used to detect and characterize single influenza virions and polystyrene nanoparticles with a radius of 30 nm (ref. 12) by measuring in the transmission spectrum either the resonance shift or mode splitting induced by the nanoscale objects. Increasing Q leads to a narrower resonance linewidth, which makes it possible to resolve smaller changes in the transmission spectrum, and thus leads to improved performance. Here, we report a whispering gallery mode microlaser-based real-time and label-free detection method that can detect individual 15-nm-radius polystyrene nanoparticles, 10-nm gold nanoparticles and influenza A virions in air, and 30 nm polystyrene nanoparticles in water. Our approach relies on measuring changes in the beat note that is produced when an ultra-narrow emission line from a whispering gallery mode microlaser is split into two modes by a nanoscale object, and these two modes then interfere. The ultimate detection limit is set by the laser linewidth, which can be made much narrower than the resonance linewidth of any passive resonator. This means that microlaser sensors have the potential to detect objects that are too small to be detected by passive resonator sensors.

Subfields: Biomedical Engineering, Biophysics, Electrical and Electronic Engineering

View Paper: https://www.semanticscholar.org/paper/a66d4c9886633b449ae91e10f3ab18f606760ac2

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In Biomedical Engineering

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Andrew M. Weiner

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Citations in the corpus

High-Q silicon nitride microresonators exhibiting low-power frequency comb initiation (2016, background): “When such resonators are integrated with other photonic and electronic devices on a silicon (Si) chip or a multichip assembly to achieve stable and tunable operation, they can bring a large range of applications onto chips, including linear and nonlinear optical information processing [2,3], spectro”
Parity–time-symmetric whispering-gallery microcavities (2013, background): “WGM modes exhibit an evanescent tail that helps to couple light in and out of the resonator, and to probe the changes in or near the resonator for ultra-high performance sensing [24,25].”
Whispering gallery mode sensors (2015, methodology): “This has been achieved using gain-functionalized microcavities, with both erbium- and ytterbium-doped microlasers [219].”