M. Weyers

Published in:

Proc. 11th European Workshop on Metalorganic Vapour Phase Epitaxy, Lausanne, Switzerland, pp. 273-278 (2005).

Abstract:

Laser diodes with output power of several Watt from a single emitter stripe or several ten Watt from a multi-emitter array or laser bar are finding increasing application in different fields of laser technology. Currently the most important field with respect to the substrate area used is diode pumping of solid state lasers (DPSSL). For years the Nd:YAG rod laser has been the workhorse for laser welding especially in the automotive industry. For such multi-kW lasers the conventional flashlamps are being replaced by laser diodes due to their higher pumping efficiency resulting in considerably reduced power consumption and cooling requirements. For this application the laser wavelength under operating conditions has to be 808 nm to match the absorption of Nd:YAG. The Yb:YAG disk laser, which is making considerable inroads into the laser machining market, has from the start been designed for diode pumping. For this material the pumping wavelength has to be 940 nm with a high precision of +/- 2 nm due to the narrow absorption band of Yb:YAG. In addition to these (and also other) pumping applications there are further applications that require a specific wavelength. One example is photodynamic therapy where drugs are activated by specific wavelengths. The drug lutrin for example accumulates in skin cancer and is activated using 730 nm laser diodes [1].

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