Low-dimensional metal-halide perovskites emerged as highly interesting materials for optoelectronics and light emission. In these materials the semiconductor octahedra are sandwiched in between comparatively large organic molecules and feature several highly attractive properties: the nanoscale dimensions of the layered structure lead to strong quantum and dielectric confinement, which for example results in strongly bound excitons. And a huge variety of molecules is available (or can be designed) to form the organic phase of the low-dimensional MHP, which provides an extensive toolbox to tailor their structural, mechanical, and optoelectronic properties.

In my talk I will discuss our recent progress in fabrication of single microcrystals of such low-dimensional perovskites, where we developed a microcrystal growth process based on dissolution and recrystallization that allows to fabricate 2D-MHP microcrystals with perfect rectangular shape. These microcrystals are single crystalline, with clean surfaces, and can function as photonic cavities.

The unique properties of SiC have driven the development of SiC-based devices for a wide range of applications, with high-power electronics being the most prominent. Commercially available 4H-SiC power devices are now integrated into numerous power systems, particularly in electric vehicles. At MRG/FORTH, we have developed SiC device technology for both high-frequency/high-power and low-frequency/high-power applications. More recently, this technology has been extended to bio-related and photonic applications, which will be presented in this talk.

The outstanding properties of SiC are also the key enablers for these emerging applications. In the biomedical field, SiC is particularly attractive because it is chemically inert, highly resistant to oxidative corrosion, exhibits negligible cytotoxicity, and offers excellent biocompatibility, including compatibility with neural tissue. In photonics, SiC is an exceptional material owing to its wide band gap, which enables operation over a broad spectral range, including the visible, while maintaining low optical absorption. In addition, its non-centrosymmetric crystal structure gives rise to second-order nonlinear optical effects. Finally, the maturity of SiC processing technology provides a significant advantage over other wide-bandgap semiconductors for both application areas.

Three rpresentative device examples will be presented: (i) a microwire-channel FET for biosensing, (ii) a neural microelectrode array, and (iii) a photonic/plasmonic nanopillar array.

In this seminar, I will present an overview of our recent activities spanning nonlinear fiber optics, gas lasers, and neurophotonics.
The first part of the talk will focus on gas-filled hollow-core fibers as a versatile platform for the development of novel laser sources, nonlinear frequency conversion, and high pulse energy Raman lasers. I will also present our recent work on coherent molecular oscillations in gas-filled hollow-core fibers, demonstrating how molecular coherence can be employed to enable highly efficient Raman frequency conversion and provide a pathway towards high repetition rate fiber lasers with high pulse energy.
The second part of the seminar will present our work on multifunctional bi-directional neural interfaces based on soft polymer optical fibers. I will discuss our recent advances in optogenetics and infrared neuromodulation for controlling brain activity in both acute and chronic settings. Finally, I will introduce our latest work on microfluidic axialtrodes, which integrate optical stimulation, electrophysiological recording, and localized drug delivery for mapping and modulating neural circuits across different brain regions.