Letter abstract


Nature Photonics 4, 46 - 49 (2010)
Published online: 13 December 2009 | Corrected online: 8 January 2010 | doi:10.1038/nphoton.2009.237

There is a Corrigendum (February 2010) associated with this article.

Subject Categories: Imaging and sensing | Novel materials and engineered structures | Nanophotonics

On-chip single nanoparticle detection and sizing by mode splitting in an ultrahigh-Q microresonator

Jiangang Zhu1, Sahin Kaya Ozdemir1, Yun-Feng Xiao1,3, Lin Li2, Lina He1, Da-Ren Chen2 & Lan Yang1


The ability to detect and size individual nanoparticles with high resolution is crucial to understanding the behaviour of single particles and effectively using their strong size-dependent properties to develop innovative products. We report real-time, in situ detection and sizing of single nanoparticles, down to 30 nm in radius, using mode splitting in a monolithic ultrahigh-quality-factor (Q) whispering-gallery-mode microresonator. Particle binding splits a whispering-gallery mode into two spectrally shifted resonance modes, forming a self-referenced detection scheme. This technique provides superior noise suppression and enables the extraction of accurate particle size information with a single-shot measurement in a microscale device. Our method requires neither labelling of the particles nor a priori information on their presence in the medium, providing an effective platform to study nanoparticles at single-particle resolution.

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  1. Department of Electrical and Systems Engineering, Washington University, St Louis, Missouri 63130, USA
  2. Department of Energy, Environmental & Chemical Engineering, Washington University, St Louis, Missouri 63130, USA
  3. Present address: State Key Laboratory for Artificial Microstructure, Institute of Modern Optics, Peking University, Beijing, China

Correspondence to: Lan Yang1 e-mail: yang@seas.wustl.edu

* In the version of this Letter originally published, The scale bars of the scanning-electron microscope images in Fig. 1 were incorrect: the scale for Fig. 1a should have been 10 μm, and the scale for Fig. 1d should have been 5 μm. In Fig. 2b, the scale of the principal y-axis was incorrect and should have been x10−7. The unit of the y-axis for the inset figure remains as x10−8. These errors have been corrected in the HTML and PDF versions.