Polydispersed Powders (Nd3+:YVO4) for Ultra Efficient Random Lasers

Autor(es)

Wetter, Niklaus U. ^[1] ; Giehl, Julia M. ^[1] ; Butzbach, Felix ^[1] ; Anacleto, Danilo ^[1] ; Jimenez-Villar, Ernesto ^[1]

Afiliação do(s) autor(es)

^[1] Ctr Lasers & Applicat, Inst Pesquisas Energet & Nucl IPEN CNEN SP, Av Prof Lineu Preses 2242, Sao Paulo, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION; v. 35, n. 4 APR 2018.
• Citações Web of Science: 3

Resumo

Random lasers hold the potential for cheap, coherent light sources that can be miniaturized and molded into any shape with several other added benefits such as speckle-free imaging; however, they require improvements specifically in terms of efficiency. This paper details for the first time a strategy for increasing the efficiency of a random laser that consists in using smaller particles, trapped between large particles to serve as absorption and gain centers whereas the large particles control mainly the light diffusion into the sample. Measurements of backscattering cone, sample absorption, reflection, and laser emission are used to determine the samples' transport mean free path, fill fractions, laser efficiency, and the average photon path lengths inside the scattering medium for backscattered pump photons. A record slope efficiency of 50% is reached by optimizing pump photon diffusion and absorption in a powder pellet composed by a polydispersed particle size distribution (smaller particles between bigger ones) from a grinded and sieved 1.33 mol% yttrium vanadate doped with neodymium crystal with mean particle size of 54 mu m. (AU)

• Processo FAPESP: 14/05965-7 - Modelamento da propagação de luz em estruturas complexas
• Beneficiário: Felix Butzbach
• Linha de fomento: Bolsas no Brasil - Programa Capacitação - Treinamento Técnico
• Processo FAPESP: 12/05141-9 - Estudo dos mecanismos de interação da luz com a matéria em meios de ganho altamente difusos
• Beneficiário: Júlia Maria Giehl
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 12/18162-4 - Desenvolvimento de lasers em meios altamente difusos para análise estrutural de tecidos
• Beneficiário: Niklaus Ursus Wetter
• Linha de fomento: Auxílio à Pesquisa - Regular