Random Lasing at Localization Transition in a Colloidal Suspension (TiO 2 @Silica).

Autor: Jiménez-Villar E; Departamento de Química Fundamental, Universidade Federal de Pernambuco, Cidade Universitária, 50670-901 Recife, PE, Brazil., da Silva IF; Departamento de Química and Departamento de Física, Universidade Federal da Paraíba, Cidade Universitária, 58051-970 João Pessoa, PB, Brazil., Mestre V; Universidade Estadual da Paraíba, CCEA, Rua Alfredo Lustosa Cabral, s/n, 58706-560 Patos, PB, Brazil., Wetter NU; Instituto de Pesquisas Energéticas e Nucleares, CNEN-IPEN, Rua Prof. Lineu Prestes 2242 - Cidade Universitária, 05508-000 São Paulo, SP, Brazil., Lopez C; Instituto de Ciencia de Materiales de Madrid (CSIC), Sor Juana Inés de la Cruz, 3, 28049 Madrid, Spain., de Oliveira PC; Departamento de Química and Departamento de Física, Universidade Federal da Paraíba, Cidade Universitária, 58051-970 João Pessoa, PB, Brazil., Faustino WM; Departamento de Química and Departamento de Física, Universidade Federal da Paraíba, Cidade Universitária, 58051-970 João Pessoa, PB, Brazil., de Sá GF; Departamento de Química Fundamental, Universidade Federal de Pernambuco, Cidade Universitária, 50670-901 Recife, PE, Brazil.
Jazyk: angličtina
Zdroj: ACS omega [ACS Omega] 2017 Jun 01; Vol. 2 (6), pp. 2415-2421. Date of Electronic Publication: 2017 Jun 01 (Print Publication: 2017).
DOI: 10.1021/acsomega.7b00086
Abstrakt: Anderson localization of light and random lasing in this critical regime is an open research frontier, which besides being a basic research topic could also lead to important applications. This article investigates the random laser action at the localization transition in a strongly disordered scattering medium composed of a colloidal suspension of core-shell nanoparticles (TiO 2 @Silica) in ethanol solution of Rhodamine 6G. The classical superfluorescence band of the random laser was measured separately by collecting the emission at the back of the samples, showing a linear dependence with pumping fluence without gain depletion. However, frontal collection showed saturation of the absorption and emission. Narrow peaks of approximately equal intensity are observed on top of the classical superfluorescence band, indicating suppression of the interaction between the peaks modes. The linewidth of these peaks is lower than that of the passive modes of the scattering medium. A method called fraction of absorbed pumping allowed us to infer that this peak's mode (localized modes) is confined to a shallow region near the input-pumping border.
Competing Interests: The authors declare no competing financial interest.
Databáze: MEDLINE
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