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HL: Fachverband Halbleiterphysik

HL 53: Optical properties

HL 53.12: Vortrag

Freitag, 29. Februar 2008, 13:30–13:45, EW 201

Subwavelength gratings as polarization selective reflectors — •Niko-Stephan Münzenrieder, Taek Lim, Alexander Bachmann, Kaveh Kashani-Shirazi, and Markus-Christian Amann — Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, 85748 Garching

Highly reflecting mirrors are an essential part of vertical cavity surface emitting lasers (VCSELs) which are known for their superior properties regarding single-mode behaviour, circular beam shape and low manufacturing costs compared to other semiconductor lasers. However, due to their cylindrical symmetry these devices are not intrinsically polarization stable. One concept to solve this issue is to use polarization selective mirrors which can be realized with grating structures. Another advantage of suitable grating designs is their high reflectivity which can improve VCSEL properties and simplify the device processing.

In this talk we present a concept for structures which can be easily integrated in established VCSEL devices with dielectric Bragg mirrors. Optimal grating parameters such as period, layer thicknesses and filling factors for given material combinations can be found using standard wave-optical methods like FDTD. Challenging aspects during the manufacturing of the gratings are the small dimensions which have to be significantly smaller than the vacuum wavelength of the VCSEL light. The technological realization of grating structures based on common dielectrics like amorphous silicon and silicon dioxide is investigated considering the compatibility to the VCSEL process.