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Optimization of broad-area GaAs  diode lasers for high powers and  high efficiencies in the temperature range 200-220 K

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Optimization of broad-area GaAs diode lasers for high powers and high efficiencies in the temperature range 200-220 K (Band 49)

Carlo Frevert (Autor)

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Leseprobe, PDF (1,6 MB)
Inhaltsverzeichnis, PDF (520 KB)

ISBN-13 (Printausgabe) 9783736999442
ISBN-13 (E-Book) 9783736989443
Sprache Englisch
Seitenanzahl 174
Auflage
Buchreihe Innovationen mit Mikrowellen und Licht. Forschungsberichte aus dem Ferdinand-Braun-Institut, Leibniz-Institut für Höchstfrequenztechnik
Band 49
Erscheinungsort Göttingen
Promotionsort TU Berlin
Erscheinungsdatum 11.07.2019
Allgemeine Einordnung Dissertation
Fachbereiche Physik
Elektrotechnik
Schlagwörter Physik, Elektrotechnik,Basic principles of AlGaAs, Lasing threshold, Influence of laser parameters, Bulk conductivity
Beschreibung

This work focuses on the development of AlGaAs-based diode laser (DL) bars optimized for reaching highest powers and efficiencies at low operation temperatures. Specifically, the quasi continuous wave (QCW) pumping of cryogenically cooled Yb:YAG solid-state lasers is targeted, setting requirements on the wavelength (940 nm), the pulse conditions (pulse length 1.2 ms) and frequency (10 Hz) as well as the lowest DL operating temperature THS ~ 200 K, consistent with economic cooling. High fill-factor bars for QCW operation are to reach high optical performance with optical output powers of P  1.5 kW and power conversion efficiencies of ŋE  60% at these power levels. Understanding the efficiency-limiting factors and the behavior at lower temperatures is necessary to design these devices.
Optimizations are performed iteratively in three stages. First, vertical epitaxial designs are studied theoretically, adjusted to the targeted operation temperatures and specific laser parameters are extracted. Secondly, resulting vertical designs are processed into low power single emitters and their electro-optical behavior at low currents is experimentally assessed over a wide range of temperatures. The obtained laser parameters characteristic to the vertical design are then used to extrapolate the laser’s performance up to the high targeted currents. Finally, vertical designs promising to reach the targeted values for power and efficiency are processed into high power single emitters and bars which are measured up to the highest currents. Eventually, laser bars are fabricated reaching output powers of 2 kW and efficiencies of 61% at 1.5 kW at an operation temperature of 203 K.