Jürgen Moosburger

Monolithically stacked high-power diode laser bars in quasi-continuous-wave operation exceeding 500 W

In this paper we report on quasi-continuous-wave (q-cw) operation of monolithically stacked laser diode bars. Monolithically stacked laser diode bars consist of more than one laser diode grown on top of each other. In between every two laser diodes a tunnel junction is included to ensure proper current injection to all lasers. In comparison to a standard laser operated at the same optical power level, the monolithic laser stack has a significantly reduced optical mirror load. Furthermore the required current is reduced drastically, which has positive consequences on both laser lifetime and diode driver costs. If one otherwise compares a monolithic integrated laser bar stack with a setup of three separate standard laser bars, the monolithic laser bar stack is characterized by very low costs per watt as well as high brilliance. By using monolithically stacked laser diode bars we were able to exceed an optical power of 500 W in q-cw mode and are moving to even higher output power levels. Typical wavelengths are in the range between 800 and 1000 nm.

Tayloring the optical properties of LEDs by using surface plasmon polariton gratings

The enhancement of light extraction is one of the major challenges for state of the art LEDs. Beside conventional approaches like surface roughening, metal gratings and metal nano particles offer an alternative approach for tailoring the optical properties of LEDs. The article will summarize theoretical calculations, experimental results and fabrication issues of plasmonic structures on inorganic LEDs. Furthermore a benchmark with state of the art LEDs will be given.