SKM 2023 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 43: Semiconductor lasers II
HL 43.5: Vortrag
Donnerstag, 30. März 2023, 16:15–16:30, JAN 0027
In-situ EBL fabrication of highly homogeneous micropillar laser arrays based on InGaAs quantum dots for neuromorphic computing — •Imad Limame1, Ching-Wen Shih1, Sven Rodt1, Daniel Brunner2, and Stephan Reitzenstein1 — 1Technical Univ. of Berlin, Germany — 2Univ. Bourgogne Franche-Comté, France
As classical computers are reaching their limit, especially in novel fields such as machine learning and artificial intelligence, cost-effective hardware platforms, and new computing architectures are needed. We combine reservoir computing with a nanophotonic platform in an all-optical computing architecture, taking inspiration from neuroscience. Our approach aims to utilize diffractive coupling between 900 micropillars to create a large-scale processing reservoir. Due to the high number of microlasers and the use of a spatial light modulator, laser arrays with low lasing threshold powers and high spectral homogeneity are required. We develop the necessary nanophotonic platform by optimized growth and in-situ electron beam lithography (EBL) fabrication of micropillar laser arrays. The MOCVD growth focuses on increasing the optical gain of the InGaAs quantum dots, used as the gain medium and on the design of the microresonator to decrease the lasing threshold. The realized devices feature thresholds as low as 20 μW. In the second phase, low temperature in-situ EBL is performed. In this process, first a CL map is recorded to determine the local resonance of the planar microcavity before micropillar with suitable diameter to match a target wavelength are patterned by electron beam lithography. Finally, the resulting micropillar array is investigated via photoluminescence.