Looking at state of the art of optical devices, it is evident that glass-based rare-earth-activated optical structures represent the technological pillar of a huge number of photonic applications covering Health and Biology, Structural Engineering, Environment Monitoring Systems, Lighting, Laser sources and Quantum Technologies. Among different glass-based systems, a strategic place is assigned to transparent glass-ceramics, nanocomposite materials, which offer specific characteristics of capital importance in photonics. Following this strategy, this PhD thesis exploits tin dioxide (SnO2)-based glass-ceramic activated by erbium ions (Er3+) to put the basis for the fabrication of solid state and integrated lasers. The research discussed in my PhD thesis gives a possible solution to two crucial and decisive points in the development of an optically pumped rare-earth-based laser: (i) the low absorption cross section of the rare-earth ions; (ii) the writing of channels and mirrors in the case of waveguide integrated laser, thanks to the demonstration of two innovative and unique characteristics of SnO2-based transparent glass-ceramics, i.e. luminescence sensitizing and photorefractivity. The role of SnO2 nanocrystals as rare-earth ion luminescence sensitizers allows to overcome the low absorption cross section of the Er3+ ion. The photorefractivity in range of 10-3 of SiO2-SnO2:Er3+ glass-ceramics allows applying the robust direct laser photoinscription technique on the systems to fabricate Bragg gratings and channel waveguides for waveguide integrated lasers. Based on an application-oriented approach, a comprehensive study on SiO2-SnO2:Er3+ glass-ceramic planar waveguides and monoliths, has been carried out. The work covers different research stages and aspects from the material preparation to a complete assessment of systems for the applications employing a rich number and variety of experimental techniques. The energy transfer from SnO2 to Er3+ and the efficient pumping scheme exploiting SnO2 as Er3+ luminescence sensitizers were demonstrated. The relaxation dynamic of the electronic states as well as the location of the dopant and density of states are discussed, and a specific modeling has been developed to the proof of concept realization of the considered devices. The obtained photorefractivity in range of 10-3 allowed the inscription of gratings on the fabricated SiO2-SnO2:Er3+ planar waveguides using UV laser direct writing technique. Exploiting the robust femtosecond laser micromachining, the optical waveguides were inscribed in the fabricated SiO2-SnO2:Er3+ monolithic squares. Another important outcome of this research is the design of a solid state laser with lateral pumping scheme and of an integrated waveguide laser in two different distributed feedback structures using all the parameters measured during the experimental activity.

Tin dioxide-based photonic glass-ceramics / Tran, Thi Ngoc Lam. - (2019), pp. 1-268.

Tin dioxide-based photonic glass-ceramics

Tran, Thi Ngoc Lam
2019-01-01

Abstract

Looking at state of the art of optical devices, it is evident that glass-based rare-earth-activated optical structures represent the technological pillar of a huge number of photonic applications covering Health and Biology, Structural Engineering, Environment Monitoring Systems, Lighting, Laser sources and Quantum Technologies. Among different glass-based systems, a strategic place is assigned to transparent glass-ceramics, nanocomposite materials, which offer specific characteristics of capital importance in photonics. Following this strategy, this PhD thesis exploits tin dioxide (SnO2)-based glass-ceramic activated by erbium ions (Er3+) to put the basis for the fabrication of solid state and integrated lasers. The research discussed in my PhD thesis gives a possible solution to two crucial and decisive points in the development of an optically pumped rare-earth-based laser: (i) the low absorption cross section of the rare-earth ions; (ii) the writing of channels and mirrors in the case of waveguide integrated laser, thanks to the demonstration of two innovative and unique characteristics of SnO2-based transparent glass-ceramics, i.e. luminescence sensitizing and photorefractivity. The role of SnO2 nanocrystals as rare-earth ion luminescence sensitizers allows to overcome the low absorption cross section of the Er3+ ion. The photorefractivity in range of 10-3 of SiO2-SnO2:Er3+ glass-ceramics allows applying the robust direct laser photoinscription technique on the systems to fabricate Bragg gratings and channel waveguides for waveguide integrated lasers. Based on an application-oriented approach, a comprehensive study on SiO2-SnO2:Er3+ glass-ceramic planar waveguides and monoliths, has been carried out. The work covers different research stages and aspects from the material preparation to a complete assessment of systems for the applications employing a rich number and variety of experimental techniques. The energy transfer from SnO2 to Er3+ and the efficient pumping scheme exploiting SnO2 as Er3+ luminescence sensitizers were demonstrated. The relaxation dynamic of the electronic states as well as the location of the dopant and density of states are discussed, and a specific modeling has been developed to the proof of concept realization of the considered devices. The obtained photorefractivity in range of 10-3 allowed the inscription of gratings on the fabricated SiO2-SnO2:Er3+ planar waveguides using UV laser direct writing technique. Exploiting the robust femtosecond laser micromachining, the optical waveguides were inscribed in the fabricated SiO2-SnO2:Er3+ monolithic squares. Another important outcome of this research is the design of a solid state laser with lateral pumping scheme and of an integrated waveguide laser in two different distributed feedback structures using all the parameters measured during the experimental activity.
2019
XXXI
2019-2020
Ingegneria civile, ambientale e mecc (29/10/12-)
Civil, Environmental and Mechanical Engineering
Zonta, Daniele
Ferrari, Maurizio
Zur, Lidia
no
Inglese
Settore FIS/07 - Fisica Applicata(Beni Culturali, Ambientali, Biol.e Medicin)
Settore FIS/01 - Fisica Sperimentale
Settore FIS/03 - Fisica della Materia
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/368580
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