Photonic Glasses - Tampere University of Technology

Photonic Glasses group

The Photonic Glasses group is led by Assist. Prof. Laeticia Petit.

 

We conduct research on the preparation and characterization of specialty photonic glasses, mainly laser glasses. We focus the research on understanding composition-structure-property relationship in these materials, with the goal to tailor new compositions to suit specific applications.

 

Research topics:

  • Active glasses and glass fibers/thin films

  • Active Glass-ceramics (GCs)

    • Er3+ doped GCs

    • Persistent luminescent GCs

  • Glasses for Mid-IR applications

 

Publications (Articles in refereed journals): the complete list of publications (including conference papers) can be found in TUTCRIS

 

Active glasses and glass fibers/thin films

Materials doped with rare-earth (RE) (e.g. Nd3+, Er3+, Yb3+, Tm3+) are of crucial importance in optoelectronics. Intense efforts are on-going worldwide to increase the performances of the RE doped fibers used as solid-state lasers and amplifiers. Because the local environment around the RE is of paramount importance for determining the optical properties, there is a constant interest in investigating new RE doped glasses with varied compositions with the aim to increase the solubility of RE ions (uniform and homogeneous dispersion of the RE ions in the glass matrix) enhancing the spectroscopic properties of the glasses. Our goal is to understand the fundamental effect of the glass composition on the RE solubility and RE luminescence properties.

We currently work on Er3+ doped and Yb3+, Er3+ codoped glasses which could find application as optical fibers, waveguide lasers, optical amplifiers, multicolor displayers, solid state lasers, mid-infrared lasers, and Q-switched devices Active Glass-ceramic (GC). Critical materials science and characterization questions are answered extending current capabilities to design, process and manufacture advanced optical glasses. We also work on demonstrating the feasibility of drawing fibers or of depositing thin films from the newly engineered glasses.

 

Active Glass-ceramics (GCs)

We develop new glass-ceramics using different techniques such as direct doping of particles into glass melt and glass ceramic method with the goal to be able to control the site of RE in the glass and so to improve the spectroscopic properties of the lasing material. The main challenges are

  • Glass-ceramic method: the heat treatment of RE doped glasses does not necessarily lead to the precipitation of Er3+ containing crystals as the glass ceramics method poses intrinsic limitations on the incorporation of RE in the in-situ crystals growing in this glass system.

  • Particles doping technique: how to balance the survival and dispersion of the particles. We investigate the impact of the glass crystallization on the luminescence properties of erbium.

Er3+ doped GCs: The work on the processing of glass-ceramics with nanoparticles small enough to avoid strong light scattering and with RE ions incorporated into a crystalline phase, has recently opened a new route to increase the efficiency of glass as active hosts. We investigate the impact of the glass composition on the crystallization tendency of the glass and also the effect of nucleation and growth of crystals on the structural and luminescence properties of Er3+-doped phosphate glasses.

Persistent luminescent GCs: Efforts are focused on the development of persistent luminescent glasses which could find application in emergency signalization, micro-defect sensing, optoelectronics for image storage, detectors of high energy radiation and thermal sensors. Persistent luminescence refers to the type of emission which lasts for a long time (from seconds to hours) after the removal of the irradiation source. We developed an alternative route to prepare phosphate glasses which contain particles with persistent luminescence and we now investigate the fabrication of new persistent luminescent glass in bulk, fiber and thin films emitting in the red to near-infrared range. Such new GCs could find application in the biomedical sector.

 

Glasses for Mid-IR applications

Fluoride glasses usually have lower phonon energy than oxide glasses, while oxide glasses usually have much better chemical durability, thermal stability, and mechanical strength than the fluoride glasses. In that sense, the combination of oxides and fluorides, particularly to give so-called oxyfluoro glasses, appears to be very interesting. If drawn into fibers, such glasses could be used as IR sensor.

New glass compositions are being tested in order to engineer new oxyfluoro glasses with extended transparency in the MIR range. Different techniques are used to prepare the oxyfluoride glasses: melting a mixture of oxide and fluoride constituents in a controlled atmosphere and/or melting the glass batch with F-based reagent such as for example NH4HF2.

 

 

Current members of the group

Iuliia Dmitrieva (Bachelor student since Nov. 2016): Glasses with targeted coefficient of thermal expansion

Fabien Dubos (Exchange student from Bordeaux University (Fance), Feb-May 2017): YAG containing glasses

Mikko Hongisto (Bachelor student, Feb-May 2017): Particles containing glasses

Hoang Nguyen Huy (Master Student since Nov. 2016): NaYF4 containing glasses

Arun Poudel (Master Student since Nov. 2016): 2D/3D upconverter waveguides

Julia Courtois (Exchange student from Rennes University (France), April-June 2017): Ag, Er codoped glass-ceramics

 

 

 

Updated by: Laeticia Petit, 23.02.2017 8:46.
Keywords: science and research