Probe station for active photonic devices

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Active photonic devices are key enablers for communication-, energy- or sensing-technologies. As examples, modulated light forms the backbone of the internet revolution and data centers, photovoltaics is a sustainable electrical energy source, and laser based sensing creates three-dimensional data for virtual reality and navigation applications. In the future, single photon systems will contribute to quantum technologies and ultraviolet light sources will clean our environment from viral or bacterial loads. Our research focuses on the development of novel semiconductor optoelectronic components, such as lasers, light emitting diodes (LEDs) or photodetectors. We derive and implement numerical models in order to analyze the light-matter interaction with multi-dimensional descriptions. The theoretical results are compared to structural and characterization data of existing devices, with the use of material parameters from ab-initio theory. This way, multiple projects with technology partners resulted in state-of-the-art specifications. While devices and structural data are available from technology partners, electro-optical characterization is only rudimentary in the majority of cases. However, comprehensive characterization is necessary in order to validate numerical models and understand the internal mechanisms of device operation. With this application, we aim to close this gap and plan to realize a probe station for active photonic devices. Comprehensive characterization shall be possible, such as spectral linewidths, wavelength spectra, beam properties, dynamic behaviours, single photon properties, and energy efficiencies. This leads to a systematic setup of both simulation and characterization, and a detailed comparison of calculated versus measured device properties. The validity and generality of our novel models can be evaluated and refined. In a subsequent step, they lead to design of future device generations. Current research includes the study of the electro-optical efficiency in lasers and LEDs in the material system Aluminum-Gallium-Nitride (AlGaN) for emission of ultraviolet (UV) light. Current efficiencies for UVC emitters are one order of magnitude lower than in blue or green devices in the same material system. A combination of injection efficiency, material fluctuations and optical absorption is responsible, however their individual contribution is unclear. Only a combination of characterization and simulation will clarify the root causes quantitatively. Another research direction currently pursued in our group is the realization of single photon and optical qubit sources for quantum information processing. Here, we participate in a project that aims to place luminescent molecules into a photonic crystal environment. The goal is to create a scalable quantum platform with a photonic system for information transfer. Theory needs to be complemented by measurements for optical coupling strengths or entanglement.