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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:29 |
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Conference: Bucharest University Faculty of Physics 2022 Meeting
Section: Polymer Physics
Title:
Spectral Biometrics of Discrete Cells via Fluorescence and Laser Action
Authors:
Valentin BARNA(1), Dedy SEPTIADI(2), Dhruv SAXENA(3), Riccardo SAPIENZA(3), Damiano GENOVESE(4), Luisa DE COLA(2)
Affiliation:
(1) Faculty of Physics - University of Bucharest, Bucharest, Romania
(2) Institut de Science et d’Ingénierie Supramoléculaires, Université de Strasbourg, Strasbourg, France
(3) The Blackett Laboratory, Imperial College London, London, UK
(4) Dipartimento di Chimica “Giacomo Ciamician”, Università di Bologna via Selmi 2, Bologna, Italy
E-mail
barnavalentin@yahoo.com
Keywords:
Confinement system, PMMA matrix, Lasing, Spectral fingerprints
Abstract:
Fluorescent dyes are a common bioimaging tool, whose spontaneous emission is used to monitor in real time and real space the activity of cells, organelles, and biomolecules with high resolution and sensitivity. Nonetheless, in the presence of strong excitation fields and of optical feedback, stimulated emission can overcome fluorescence and eventually lead to laser action. Lasing, compared to spontaneous emission, carries information not only on the solvating environment in the direct vicinity of the dyes, but also on the optical system (e.g., cavities, microresonators or scatterer density) that generates the amplification, since it determines at a large extent the allowed spectral and spatial properties of laser emission, i.e., the lasing modes. Here, lasing is triggered by cells floating in a low quality factor resonator composed of a disposable poly(methyl methacrylate) (PMMA) cell counting-slide, hence in absence of conventional high-reflectivity optical cavities. The exceptional spectral narrowing and the steep slope increase in the input–output energy diagram prove occurrence of laser action in presence of cells. The observed biolasing is an intrinsically dynamic signal, with large fluctuations in intensity and spectrum determined by the optical properties of the individual cell passing through the pump beam.
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