Vacancy-related centres in silicon carbide are attracting growing attention because of their appealing optical and spin properties. These atomic-scale defects can be created using electron or neutron irradiation; however, their precise engineering has not been demonstrated yet. Here, silicon vacancies are generated in a nuclear reactor and their density is controlled over eight orders of magnitude within an accuracy down to a single vacancy level. An isolated silicon vacancy serves as a near-infrared photostable single-photon emitter, operating even at room temperature. The vacancy spins can be manipulated using an optically detected magnetic resonance technique, and we determine the transition rates and absorption crosssection, describing the intensity-dependent photophysics of these emitters. The on-demand engineering of optically active spins in technologically friendly materials is a crucial step toward implementation of both maser amplifiers, requiring high-density spin ensembles, and qubits based on single spins.
A novel all-organic host-guest system for emission in the NIR is introduced and investigated with respect to its opto-electronic processes. The good agreement between theoretical and experimental results highlights the model character of this system and its potential for electroluminescent application. Comparative measurements provide access to the recombination mechanisms on molecular length scale and show that the emission behavior of the device under operation is controlled by charge carrier dynamics.
Industrial high-precision 3D Printing (HP3DP) via two-photon absorption (TPA) provides freedom in design for the fabrication of novel products that are not feasible with conventional techniques. Up to now, 2PP-fabrication has only been used for structures on the micrometer scale due to limited traveling ranges of the translation stages and the field-of-view (FoV) of microscope objectives (diameters below 0.5 mm). For industrial applications, not only high throughput but also scalability in size is essential. For this purpose, this contribution gives insights into different manufacturing strategies composed of varying exposure modes, fabrication modes, and structuring modes, which enable the generation of large-scale optical elements without relying on stitching. With strategies like stage-only mode or synchronized movement of galvoscanners and translation stages, optical elements with several millimeters in diameter and freeform shape can be fabricated with optical surface quality.
The demand of sophisticated components is continuously increasing, driven by big data, IoT, and Industry 4.0. Reducing process cost is impacting all levels in a vast majority of products. 3D printing is typically restricted to additive fabrication within one material class, structures are limited in size, shape, surface finish, requiring supporting structures. This prevents high quality photonic components. High precision 3D printing is utilizing a multiphoton process which is a powerful tool for prototyping of miniaturized designs in automated, scalable processes for products in photonic or medical packaging. While most of the 3D systems are still working rather on a lab than on an industrial scale with typically very long fabrication times ranging from minutes to hours for a single microlens, the process can be boosted significantly to a fabrication time in the range of seconds per lens using different fabrication strategies, resulting in microlenses with high optical quality. This saves more than 90 % of the fabrication time compared to standard fabrication, and 1 cm2 lens arrays with high filling factors can be fabricated within only a few hours — a big step towards high throughput and industrial scalability.
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