ABSTRACT
Increasing Yb3+ absorption efficiency is currently desired in a number of applications including bio-imaging, photovoltaics, near infrared driven photocatalysis or ultra-short pulsed solid-state lasers. In this work, silver nanoparticles, which are connected forming disordered networks, have been self-assembled on Yb3+ doped RbTiOPO4 crystals to produce a remarkable enhancement of Yb3+ absorption, and hence in the photoluminescence of this ion. The results are interpreted taking into account the near-field response of the plasmonic networks, which display strong amplification of the electric field at the maximum of Yb3+ excitation at around 900 nm, together with the anisotropic character of the Yb3+ transitions in RbTiOPO4. We show that in the near field regime, the scattering of the plasmonic networks produces additional polarization field components to those of the incident field, which allows access to the largest transition dipolar moment of Yb3+ ions in RbTiOPO4. As a result, a much more efficient route for Yb3+ excitation takes place at the immediacy of the plasmonic networks. This work provides fundamental insights for improving the optical properties of rare earth ions by the suitable design of metallic nanoparticle arrangements, and constitutes a promising step towards the development of new multifunctional solid-state lasers.
ABSTRACT
Ferroelectric domain patterns are used as templates on which rare earth doped high refractive index nanoparticles activated with trivalent rare earth ions (RE(3+)) are selectively assembled on domain surfaces with a specific polarization. Two-dimensional luminescent heterostructures, with sizes and geometries defined by the ferroelectric patterning are achieved. The process of incorporation and consolidation of the optically active nanoparticles into the alternate domain structures leads to luminescent ring-shaped arrangements with innovative geometries and to a micrometer spatial control of the trivalent rare earth ion emitters. Multicolor emission systems and the possibility of chromatic switching at the micrometer scale among the three different compounds forming the two dimensional structure is demonstrated.
Subject(s)
Metals, Rare Earth/chemistry , Microscopy, Fluorescence/methods , Nanoparticles/chemistry , Niobium/chemistry , Optics and Photonics/methods , Oxides/chemistry , Luminescence , Microscopy, Electron, Scanning , Spectrum Analysis, Raman , X-Ray DiffractionABSTRACT
We report on a simple and accurate method for determination of thermo-optical and spectroscopic parameters (thermal diffusivity, temperature coefficient of the optical path length change, pump and fluorescence quantum efficiencies, thermal loading, thermal lens focal length, etc) of relevance in the thermal lensing of end-pumped neodymium lasers operating at 1.06- and 1.3- microm channels. The comparison between thermal lensing observed in presence and absence of laser oscillation has been used to elucidate and evaluate the contribution of quantum efficiency and excited sate absorption processes to the thermal loading of Nd:YAG lasers.
Subject(s)
Hot Temperature , Lasers, Solid-State , Lenses , Luminescence , Spectrum AnalysisABSTRACT
In this Letter we have used the optical pump induced thermal loading to drive Nd(3+) a doped Sr(0,47)Ba(0.53)(Nb)(3))(2) laser crystal during laser operation through its ferroelectric phase transition. We demonstrate that lasing is possible below, at, and above phase transition. For temperatures close to (approximately 105 degrees C) the spatial distribution of laser radiation is remarkably affected. This feature, which leads to a laser gain depression, can be explained in terms of the strong temperature dependence of the thermo-optic coefficient during phase transition. Additionally, the visible radiation generated by intracavity self-frequency doubling disappears when the phase transition is undergone, showing a bistable behavior. The results provide fundamental information on physical parameters along the phase transition and will stimulate further work in the fields of nonlinear optics, optical switching, and data storage.
