title: Infrared-to-Visible Light Conversion in Er(3+) -Yb(3+) :Lu3 Ga5 O12 Nanogarnets.
abstract: Er(3+) -Yb(3+) co-doped Lu3 Ga5 O12 nanogarnets were prepared and characterized; their structural and luminescence properties were determined as a function of the Yb(3+) concentration. The morphology of the nanogarnets was studied by HRTEM. Under 488 nm excitation, the nanogarnets emit green, red, and near-infrared light. The decay curves for the ((4) S3/2 , (2) H11/2 ) and (4) F9/2 levels of the Er(3+) ions exhibit a non-exponential nature under resonant laser excitation and their effective lifetimes are found to decrease with an increase in the Yb(3+) concentration from 1.0 to 10.0 mol %. The non-exponential decay curves are well fitted to the Inokuti-Hirayama model for S=8, indicating that the mechanism of interaction for energy transfer between the optically active ions is of dipole-quadrupole type. Upon 976 nm laser excitation, an intense green upconverted emission is clearly observed by the naked eyes. A significant enhancement of the red-to-green intensity ratio of Er(3+) ions was observed with an increase in Yb(3+) concentration. The power dependence and the dynamics of the upconverted emission confirm the existence of two-photon upconversion processes for the green and red emissions.
authors.affiliation: Department of Physics, Yogi Vemana University, Kadapa-, 516 003, India.
authors.forename: Mamilla
authors.initials: M
authors.lastname: Rathaiah
authors.affiliation: Department of Physics, Yogi Vemana University, Kadapa-, 516 003, India.
authors.forename: Pamuluri
authors.initials: P
authors.lastname: Haritha
authors.affiliation: School of Information and Communications, Gwangju Institute of Science and Technology, 123 Cheomdan-gwagiro, Buk-gu, Gwangju, 500-712, South Korea.
authors.forename: Kadathala
authors.initials: K
authors.lastname: Linganna
authors.affiliation: Departamento de Física, MALTA Consolider Team, Instituto Universitario de Materiales y Nanotecnología (IMN), Instituto Universitario de Estudios Avanzados en Física, Atómica, Molecular y Fotónica (IUdEA), Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife, Spain.
authors.forename: Virginia
authors.initials: V
authors.lastname: Monteseguro
authors.affiliation: Departamento de Física, MALTA Consolider Team, Instituto Universitario de Materiales y Nanotecnología (IMN), Instituto Universitario de Estudios Avanzados en Física, Atómica, Molecular y Fotónica (IUdEA), Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife, Spain.
authors.forename: Inocencio Rafael
authors.initials: IR
authors.lastname: Martín
authors.affiliation: Departamento de Física, MALTA Consolider Team, Instituto Universitario de Materiales y Nanotecnología (IMN), Instituto Universitario de Estudios Avanzados en Física, Atómica, Molecular y Fotónica (IUdEA), Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife, Spain.
authors.forename: Antonio Diego
authors.initials: AD
authors.lastname: Lozano-Gorrín
authors.affiliation: Department of Physics, Government Degree College, Satyaveedu-, 517 588, India.
authors.forename: Palamandala
authors.initials: P
authors.lastname: Babu
authors.affiliation: Department of Physics, Sri Venkateswara University, Tirupati-, 517 502, India.
authors.forename: Chalicheemalapalli Kulala
authors.initials: CK
authors.lastname: Jayasankar
authors.affiliation: Departamento de Física, MALTA Consolider Team, Instituto Universitario de Materiales y Nanotecnología (IMN), Instituto Universitario de Estudios Avanzados en Física, Atómica, Molecular y Fotónica (IUdEA), Universidad de La Laguna, 38200 San Cristóbal de La Laguna, Santa Cruz de Tenerife, Spain.
authors.forename: Victor
authors.initials: V
authors.lastname: Lavín
authors.affiliation: Department of Physics, Yogi Vemana University, Kadapa-, 516 003, India. vvramuphd@gmail.com.
authors.forename: Vemula
authors.initials: V
authors.lastname: Venkatramu
mesh_terms: D004871:Erbium / Q000737:chemistry*; D005708:Gallium / Q000737:chemistry*; D007259:Infrared Rays; D008027:Light; D008187:Lutetium / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D049329:Nanostructures; D033362:Powder Diffraction; D013057:Spectrum Analysis / Q000379:methods; D015018:Ytterbium / Q000737:chemistry*
chemical_list: D008187:Lutetium; D004871:Erbium; D005708:Gallium; D015018:Ytterbium
keywords: dynamics; lifetime; luminescence; nanogarnets; upconversion