Lunedì alle ore 11:00 presso l'aula seminari della Palazzina RM004 si terrà un seminario del prof. Mircea Guina, Direttore del Gruppo Semiconduttori III-V dell'Optoelectronics Research Centre (Tampere University of Technology - Finlandia) dal titolo: Novel III-V optoelectronic heterostructures and high-brightness semiconductor lasers
Novel III-V optoelectronic heterostructures and high-brightness semiconductor lasers
Prof. Mircea Guina
Optoelectronics research centre, Tampere University of Technology
The seminar will start with an overview of key research areas at the Optoelectronics Research Centre, Tampere University of Technology covering the following topics:
· Development of epitaxial technology for novel III-V alloys and nanostructures;
· Development of novel types of semiconductor light sources;
· Development of III-V multi-junction solar cells;
· Development of optoelectronics chips for photonic integrated circuits.
As a more detailed scientific presentation, the seminar includes an introduction to technological concepts underpinning the development of vertical-external-cavity surface-emitting lasers (VECSELs). These high-brightness light sources draw important advantages from both semiconductor and solid-state lasers: the simplicity to engineer the emission properties of semiconductors is combined with the functionality of solid-state lasers owing to the use of external cavity architectures. This combination has enabled obtaining outstanding results in terms of wavelength coverage (from visible to mid-IR), high-power (100W-level), single-frequency operation, efficient intracavity frequency conversion, and ultra-short pulse generation (down to sub-picosecond range with GHz repetition rate). Achievements concerning wavelength extension of VECSELs towards visible part of the optical spectrum (675 nm) by using GaInP/AlGaInP/GaAs heterostructures, and towards the mid-IR (2 µm) by using InGaSb/GaSb quantum-wells, will be presented. Furthermore, the development of VECSELs emitting yellow-orange radiation with a record power of more than 20 W is highlighted. These developments have been fostered by the need to attain unique combination of output parameters for applications in spectroscopy, laser cooling, laser projection, life-science, or microscopy, while using an affordable and compact laser platform. Key application of VECSELs will be reviewed.
Prof. Mircea GUINAis the Head of the III-V Optoelectronics Group at the Optoelectronics Research Centre, Tampere University of Technology since 2008. He conducts scientific work related to molecular beam epitaxy of novel heterostructures and optoelectronics devices. His current projects are concerned with the development of ordered QD- and NW-based nanostructures for quantum optics, epitaxy of III-Bi-V alloys, the development of novel semiconductor lasers and amplifiers, and the development of ultra-high efficiency multijunction solar cells. He has published more than 140 journal papers, several book chapters, holds 4 international patents, and has given numerous invited talks at major optoelectronics conferences. He is the Director of the International Summer School “New Frontiers in Optical Technologies”, the largest photonics summer school in Europe, which he established in 2001.
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