Probe station for active photonic devices

有源光子器件是通信、能源或传感技术的关键推动因素。例如，调制光构成了互联网革命和数据中心的支柱，光伏是一种可持续的电能来源，基于激光的传感为虚拟现实和导航应用创造了三维数据。未来，单光子系统将为量子技术做出贡献，紫外线光源将清除我们环境中的病毒或细菌。我们的研究重点是开发新型半导体光电子元件，如激光器、发光二极管(LED)或光电探测器。为了用多维描述分析光与物质的相互作用，我们推导并实现了数值模型。利用从头算理论中的材料参数，将理论结果与现有器件的结构和表征数据进行了比较。通过这种方式，与技术合作伙伴的多个项目产生了最先进的规范。虽然设备和结构数据可以从技术合作伙伴那里获得，但在大多数情况下，光电表征只是初级的。然而，为了验证数值模型和了解器件运行的内部机制，需要进行全面的表征。通过这一应用，我们的目标是缩小这一差距，并计划实现一个用于有源光子设备的探测站。应能够进行综合表征，例如光谱线宽、波长光谱、光束特性、动态特性、单光子特性和能量效率。这导致了模拟和表征的系统设置，以及计算和测量的器件特性的详细比较。我们的新模型的有效性和通用性是可以评估和改进的。在接下来的步骤中，它们将导致未来几代设备的设计。目前的研究包括研究铝-氮化镓(AlGaN)材料体系中激光器和LED的电光效率，以发射紫外光。在相同的材料体系中，UVC发射器的电流效率比蓝色或绿色设备低一个数量级。注射效率、材料波动和光吸收的组合是原因，但它们各自的贡献尚不清楚。只有将定性和模拟相结合，才能定量地阐明根本原因。本课题组目前追求的另一个研究方向是实现用于量子信息处理的单光子和光学量子比特源。在这里，我们参与了一个旨在将发光分子放置到光子晶体环境中的项目。其目标是创建一个具有光子系统的可扩展量子平台，用于信息传输。理论需要通过测量光学耦合强度或纠缠来补充。

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.