Luminescence plasmon enhancement and laser at the nanoscale in a Nd3+ based solid state gain medium

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Física de Materiales. Fecha de lectura: 11-12-201

Plasmon assisted Nd3+-based solid-state nanolaser

Solid-state lasers constitute essential tools in a variety of scientific and technological areas, being available in many different designs. However, although nanolasing has been successfully achieved for dyes and semiconductor gain media associated with plasmonic structures, the operation of solid-state lasers beyond the diffraction limit has not been reported yet. Here, we demonstrate room temperature laser action with subwavelength confinement in a Nd3+-based solid-state laser by means of the localized surface plasmon resonances supported by chains of metallic nanoparticles. We show a 50% reduction of the pump power at threshold and a remarkable 15-fold improvement of the slope efficiency with respect to the bulk laser operation. The results can be extended to the large diversity of solid-state lasers with the subsequent impact on their applicationsThis work has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under projects MAT2013-43301-R and FIS2013-41184-P and Comunidad de Madrid under grant S2013/MIT-2740

Blue SHG enhancement by silver nanocubes photochemically prepared on a RbTiOPO4 ferroelectric crystal

This is the peer reviewed version of the following article: Blue SHG enhancement by silver nanocubes photochemically prepared on a RbTiOPO4 ferroelectric crystal, which has been published in final form at http://doi.org/10.1002/adma.201401603. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived VersionsSilver nanocubes with low size dispersion have been selectively photo-deposited on the positive surface of a periodically poled RbTiOPO 4 ferroelectric crystal. The obtained nanocubes show preferential orientations with respect to the substrate suggesting ep itaxial growth. The plasmonic resonances supported by the nanocubes are exploited to enhance blue SHG at the domain wallsThis work has been supported by the Spanish Government under projects MAT2010–17443, MAT2011–29255-C02–02 and MAT2013– 43301-R, Comunidad de Madrid under grant S2009/1756 and Generalitat de Catalunya under project 2009SGR23

Controlling solid state gain media by deposition of silver nanoparticles: from thermally-quenched to plasmon-enhanced Nd3+ luminescence

We show the possibility of controlling the optical properties of Nd3+ laser ions by using different configurations of metallic nanoparticles (NPs) deposited on a solid state gain medium. In particular, we analyze the effect of two different silver NP arrangements on the optical properties of Nd3+ ions in LiNbO3: a two-dimensional (2D) high density and disordered Ag NP distribution and a one-dimensional (1D) long single chain of Ag NPs. We demonstrate that while the 2D disordered distribution produces a thermal quenching of the Nd3+ luminescence, the 1D single chain leads to the enhancement of the fluorescence from the 4F3/2 metastable state. The experimental data are theoretically interpreted by taking into account the different character, radiative or non-radiative, of the localized surface plasmonic modes supported by the Ag nanoparticle distributions at the excitation wavelength. The results point out the capabilities of rare earth ions as optical tools to probe the local plasmonic fields and are relevant to determine the optimal configuration of metallic arrays to improve the performance of potential rare earth ion based sub-micrometer lasers.This work has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under projects MAT2010-17443 and MAT2013-43301-R and Comunidad de Madrid under grant S2013/MIT-2740. CT and JA acknowledge financial support from Project FIS2013-41184-P of the Spanish MINECO, project ETORTEK NANOGUNE’14 of the Department of Industry of the Basque Government, and from the Department of Education of the Basque Government, IT756-13 of consolidated groups. MOR acknowledges Ramon y Cajal Contract from Spanish MINECO. LSG acknowledges FPU13/02476 grant from the Spanish Ministry of Education.Peer Reviewe

Polarization-selective enhancement of Nd3+ photoluminescence assisted by linear chains of silver nanoparticles

A control of the emission of Nd3+ ions by polarization-dependent plasmon modes, supported by chains of silver nanoparticles deposited on the surface of a Nd3+:LiNbO3 crystal, is demonstrated. By combining micro-fluorescence measurements with theoretical calculations based on the boundary-element method, we explain how the energy splitting between the longitudinal and transverse modes of silver nanoparticle chains produces a selective enhancement of the Nd3+ emission Stark lines: exciting radiative modes of silver nanoparticle chains with light polarized parallel to their axis produces a spectral-selective intensification of the π-character Stark transitions of Nd3+ located in the vicinity of the silver nanoparticles. The results are relevant to the design of devices for coherent generation at the nanoscale based on rare earth solid state gain media.This work has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under projects MAT2010-17443 and MAT2013-43301-R and Comunidad Autónoma de Madrid under project S2013/MIT-2740. MOR acknowledges Ramon y Cajal Contract from Spanish MINECO. LSG acknowledges FPU13/02476 grant from the Spanish Ministry of Education. CT and JA acknowledge financial support from Project FIS2013-41184-P of the Spanish Ministry of Economy and Competitiveness (MINECO), project ETORTEK 2014-15 of the Department of Industry of the Basque Government, and from the Department of Education of the Basque Government, IT756-13 of consolidated groups.Peer reviewe

Selective Plasmon Enhancement of the 1.08 μm Nd³⁺ Laser Stark Transition by Tailoring Ag Nanoparticles Chains on a PPLN <i>Y</i>‑cut

Selective photoluminescence enhancement of the specific Nd³⁺ Stark transition for which laser gain has been obtained in Nd³⁺/LiNbO₃ is demonstrated by means of plasmonic resonances with the appropriate symmetry configuration. By using the nonpolar <i>Y</i>-cut of a periodically poled LiNbO₃ crystal as platform for photoreduction of metallic nanostructures, periodically distributed chains of Ag nanoparticles oriented parallel to the ferroelectric <i>c</i>-axis are obtained. This alternative metallic nanostructure configuration supports the resonance between the localized surface plasmon and exclusively the π-polarized Stark laser line of Nd³⁺ ions at 1.08 μm, while maintaining the remaining crystal field transitions unchanged. The work provides the experimental proof on how plasmonic-based optical antennas can be used to influence selectively rare earth optical Stark transitions to improve the performance of solid state laser gain media

Plasmon-Assisted Nd³⁺-Based Solid-State Nanolaser

Solid-state lasers constitute essential tools in a variety of scientific and technological areas, being available in many different designs. However, although nanolasing has been successfully achieved for dyes and semiconductor gain media associated with plasmonic structures, the operation of solid-state lasers beyond the diffraction limit has not been reported yet. Here, we demonstrate room temperature laser action with subwavelength confinement in a Nd³⁺-based solid-state laser by means of the localized surface plasmon resonances supported by chains of metallic nanoparticles. We show a 50% reduction of the pump power at threshold and a remarkable 15-fold improvement of the slope efficiency with respect to the bulk laser operation. The results can be extended to the large diversity of solid-state lasers with the subsequent impact on their applications

Plasmonics of Opal Surface: A Combined Near- and Far-Field Approach

An opal plasmonic sample, constituted by a hexagonal arrangement of metallized silica spheres, presents remarkable optical properties due to the mixing of periodic arrangement and singularities at the sphere touching points. It is therefore an interesting candidate for exploiting the excitation of both localized and propagating surface plasmons. Several channels of excitation based on these properties or exploiting a certain level of disorder are evidenced, opening new routes for the efficient excitation of plasmons on a wide spectral range. The versatility of such a hybrid system is evidenced in the context of two complementary experiments: specular reflective spectrometry and photoemission electron microscopy. Both techniques offer different points of view on the same physical phenomenon, and the link between them is discussed. Such experiments evidence the opportunities offered by these two-dimensional hybrid materials in the context of nanophotonics