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Analysis of individual nanodroplets and nanoparticles through a semiconductor optomechanical sensor

Abstract : Due to their small size, nanomechanical systems exhibit a strong response to external perturbations, which has led to remarkable progress in mass spectrometry over the last decade. The combination with optomechanical concepts should lead to further advances, thanks to the unprecedented sensitivity and bandwidth of optomechanical techniques. In this thesis, we have used the intense optomechanical coupling at work in gallium arsenide disk resonators to perform continuous and parallel optical tracking of multiple modes of vibration of a disk, optically excited by sinusoidal modulation of the input laser. A multi-physics model was developed to describe the optomechanical experiments under these conditions, including photothermal forces, radiation pressure, electrostriction, and non-linear absorption in the device. It allowed a quantitative interpretation of the multi-mode optical output signal, which carries useful detection information when an external stimulus disturbs the disk. Solid nanoparticles of femto-gram mass, and liquid droplets of a few tens of attolitres, were detected when they landed on a disk resonator, by measuring the frequency shifts of optical and mechanical resonances of the latter. These shifts were modelled using analytical and numerical tools, and allowed the mass and geometry of the objects adsorbed on the resonator to be assessed. This work demonstrates the effectiveness of optomechanical devices for mass measurement and, more generally, for the dual mechanical and optical analysis of nanometric objects. The first steps are thus taken towards a rapid and quantitative method for identifying biological particles and studying liquids at the nanometric scale.
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https://hal-univ-paris.archives-ouvertes.fr/tel-03784536
Contributor : Samantha Sbarra Connect in order to contact the contributor
Submitted on : Friday, September 23, 2022 - 10:36:05 AM
Last modification on : Sunday, September 25, 2022 - 3:42:27 AM

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  • HAL Id : tel-03784536, version 1

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Samantha Sbarra. Analysis of individual nanodroplets and nanoparticles through a semiconductor optomechanical sensor. Physics [physics]. Université de Paris, Paris, FRA., 2021. English. ⟨NNT : ⟩. ⟨tel-03784536⟩

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