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Q: Quantenoptik

Coherent seeding of a bar of 25 broad area lasers — •Volker Raab and Ralf Menzel — Universität Potsdam, Am Neuen Palais 10, 14469 Potsdam

We present first results on the coherent coupling of a bar of

high-power broad-area diode lasers with AR coated outcoupling facets.

By means of a diffractive beam-splitter we generate 25 copies of a

seeding laser with good beam quality. These diffraction orders are

then coupled into the 25 emitters of the laser bar which

are driven at about 600 mA pumping current each.

The diode lasers reject the amplified seeding light which is redirected

back onto the diffractive optic where the (remaining) relative

coherence of the separately amplified beams can be determined. We find

that a large part of the coherence of the 25 beams is pertained.

This opens way for the setup of an external resonator in which an

array of lasers operates coherently. This would result in an output

power that scales with the number of lasers at a total beam quality

identical to that of the single emitter.

(Funded by the BMBF and VDI)