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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-23 18:23 |
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Conference: Bucharest University Faculty of Physics 2017 Meeting
Section: Optics, Spectroscopy, Plasma and Lasers
Title:
Temporal resolved fluorescence emission by laser pumped microliter droplets in air
Authors:
Boni MIHAI (1,2), Ionut Relu ANDREI(1), Angela STAICU(1), Mihail Lucian PASCU(1,2)
*
Affiliation:
1) National Institute for Laser, Plasma and Radiation Physics, P.O.Box MG-6, RO-077125 Bucharest-Magurele, Romania
2) Faculty of Physics, University of Bucharest, RO-077125 Bucharest-Magurele, Romania
E-mail
mihai.boni@inflpr.ro
Keywords:
Laser induced fluorescence, lasing, laser dye, microdroplets, optical signal sampling, Rhodamine 6G
Abstract:
The fluorescence emission of a single pendant microliter droplet in air containing Rhodamine 6G in water at several concentrations when irradiated with 532 nm single laser pulse is reported. The measurement of temporal evolution of emission spectra by varying signal acquisition gate width of the spectrograph used to measure fluorescence and the gate delay with respect to pumping pulse emission time moment represents the main novelty of this study. Fluorescence amplification due to internal reflection in the droplet as a quasispherical closed optical resonator is produced. Two peaks are lased that depend of solution concentration, emission-sampling time with respect to gate delay and pumping energy [1,2].The high resolution emission spectra for 1 µl and 1.5 µl droplets containing 5×10^-4M Rhodamine 6G dye/water solution pumped into a convergent geometry of irradiation at 18 mJ energy show a complex spectral structure of the resonant peak. This shows few oscillations, which form a ripple structure with an oscillation upon which are superimposed resonances whose basic period is dependent of the solution refractive index, not of the droplet dimensions. In addition, the influence on the droplet emission spectra of the dye solution doped with TiO2 nanoparticles was investigated [3]. The laser-induced emission spectra are analyzed function of TiO2 concentration, pH of the solution and laser pump energy.
References:
1. M. Boni, V. Nastasa, A. Staicu, I.R. Andrei, and M.L. Pascu, Romanian Rep. Phys. 67, 1278 (2015).
2. M. Boni, V. Nastasa, I.R. Andrei, A. Staicu, and M.L. Pascu, Biomicrofluidics 9, 014126 (2015).
3. M. Boni, A. Staicu, I.R. Andrei, A. Smarandache, V. Nastasa, M. Comor,Z. Saponjic, M.L. Pascu,COLSUA 519, 238–244, (2017)
Acknowledgement:
The present research was supported by the project PN-III-P2-2.1-PED-2016-0420 and by the Nucleu programme-contract project 1647/2016.
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