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Proceedings Paper

Nanofiber nanoscopy and quantum noise limited biosensing (Conference Presentation)
Author(s): Lars Madsen

Paper Abstract

Biology is a longstanding frontier for quantum metrology, where high optical intensities are frequently required to get sufficient signal, but lead to specimen damage [1]. In this regime quantum-noise limited sensitivity allows higher signal to noise or reduced optical intensities. I will give an overview of efforts in the Queensland Quantum Optics Laboratory to apply nanofiber based quantum-noise limited biosensor to biological measurements and our recent progress in nanofiber characterization. We demonstrate a quantum noise limited biosensor capable of detecting single unlabelled biomolecules with radii below 5 nm [2]. The nanoparticles are illuminated through a microscope objective and the scattered light is collected by a nanofiber. The collected light is detected with a heterodyne detector and obtains a quantum-noise limited performance down to 5 Hz and particle tracking with 1 kHz bandwidth. This detection performance opens for observation of biomolecular movements avoiding large biomarkers. We present a method for directly measuring the evanescent field of an optical nanofiber [3]. Unlike SEM-based methods, this method is non-destructive and yields a full profile of the nanofiber within minutes of fabrication. We obtain the radius with a resolution of 0.7 nm in 10 milliseconds. The method allows quality control and calibration of optical nanofibers for precision experiments for example as in the above mentioned biosensor. References [1] K. C. Neuman et al. Biophysics Journal 77, 2856-2863 (1999). [2] N. Mauranyapin, L. Madsen et al. Nature Photonics, in press July (2017) [3] L. Madsen, et al. Nano Letters, 16, 7333−7337 (2016)

Paper Details

Date Published: 14 March 2018
Proc. SPIE 10518, Laser Resonators, Microresonators, and Beam Control XX, 1051803 (14 March 2018); doi: 10.1117/12.2287301
Show Author Affiliations
Lars Madsen, The Univ. of Queensland (Australia)

Published in SPIE Proceedings Vol. 10518:
Laser Resonators, Microresonators, and Beam Control XX
Alexis V. Kudryashov; Alan H. Paxton; Vladimir S. Ilchenko, Editor(s)

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