On thermal effects in solid-state lasers: The case of ytterbium-doped materials

• Published in: Progress in quantum electronics 2006-01, Vol.30 (4), p.89-153
• Main Authors: Chénais, Sébastien, Druon, Frédéric, Forget, Sébastien, Balembois, François, Georges, Patrick
• Format: Article
• Language: English
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Diode-pumped lasers; Doped-insulator lasers and other solid state lasers; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Laser materials; Lasers; Optical materials; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of bulk materials and thin films; Optics; Physics; Solid-state lasers; Thermal lensing; Thermo-optical effects; Thermooptical and photothermal effects; Ytterbium
• ISSN: 0079-6727; 1873-1627
• DOI: 10.1016/j.pquantelec.2006.12.001

A review of theoretical and experimental studies of thermal effects in solid-state lasers is presented, with a special focus on diode-pumped ytterbium-doped materials. A large part of this review provides however general information applicable to any kind of solid-state laser. Our aim here is not to make a list of the techniques that have been used to minimize thermal effects, but instead to give an overview of the theoretical aspects underneath, and give a state-of-the-art of the tools at the disposal of the laser scientist to measure thermal effects. After a presentation of some general properties of Yb-doped materials ( Section 1), we address the issue of evaluating the temperature map in Yb-doped laser crystals, both theoretically and experimentally ( Section 2). This is the first step before studying the complex problem of thermal lensing ( Section 3). We will focus on some newly discussed aspects, like the definition of the thermo-optic coefficient: we will highlight some misleading interpretations of thermal lensing experiments due to the use of the d n/d T parameter in a context where it is not relevant. Section 4 will be devoted to a state-of-the-art of experimental techniques used to measure thermal lensing. Eventually, in Section 5, we will give some concrete examples in Yb-doped materials, where their peculiarities will be pointed out.