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O: Fachverband Oberflächenphysik
O 60: Poster Session IV (Solid/liquid interfaces; Semiconductors; Oxides and insulators; Graphene; Plasmonics and nanooptics; Electronic Structure; Surface chemical reactions; Heterogeneous catalysis)
O 60.87: Poster
Wednesday, March 16, 2011, 17:30–21:00, P4
Plasmonic Collimation of near-IR Laser Diodes — •Xinghui Yin1,2, Thomas Taubner2,3, and Peter Loosen1,2 — 1Institute for Technology of Optical Systems, RWTH Aachen University, Steinbachstr. 15, 52074 Aachen — 2Fraunhofer Institute for Laser Technology ILT, Steinbachstr. 15, 52074 Aachen — 3I. Institute of Physics (IA), RWTH Aachen University, Sommerfeldstr. 14, 52074 Aachen
Laser diodes are compact and versatile components for numerous applications. However, they show a strongly asymmetric beam-profile in the far-field due to the confined dimensions of their emitting area (ca. 1 µ m × 5 µ m). Currently, high-index cylindric lenses are employed to reduce the beam divergence. This is a nonmonolithic, costly approach as lenses have to be manually adjusted.
We investigate beam collimation in one direction by effectively enlarging the emitting area. To do so, we use a plasmonic structure consisting of a slit and a grating structured in a gold layer directly on top of the laser facet. Previous work done by Ebbesen et al [1] confirm the beaming properties of such structures. Capasso et al [2] successfully combined plasmonic collimators and Quantum Cascade Lasers at wavelengths of λ = 9.8 µ m. We optimize the structure parameters for near-infrared wavelengths (λ =960 nm). Using the obtained parameters, we fabricate the plasmonic collimator and characterize it.
[1] Ebbesen et al., Beaming Light from a subwavelength Aperture, 2002, Vol 297, Science
[2] Capasso et al., Nature Photonics, 2008