Conference Agenda

A compact time-domain optical coherence tomography (TD-OCT) system driven by a fiber-coupled GaSb superluminescent diode (SLD) operating near 2 µm is reported. The SLD delivers amplified spontaneous emission (ASE) with a spectral full-width half-maximum (FWHM) bandwidth of 65 nm at a drive current of 150 mA. The OCT imaging system achieves an axial resolution of approximately 300 µm in air and was evaluated using structured samples comprising printed patterns beneath scattering paint layers. En-face OCT slices and reconstructed B-scans clearly resolves buried features and thickness variations within the coating.

We propose a deterministic method for ring-shaped beam synthesis in coherent beam combining (CBC) systems using phase-only control. A calibrated propagation operator is inverted via a Tikhonov-regularized pseudoinverse to directly compute the required phase distribution in a single step, eliminating iterative optimization. The approach enables fast, stable beam formation and maintains ring structure. Simulations demonstrate accurate intensity shaping and robust performance, making the method suitable for real-time structured beam generation.

Photonic crystals (PhCs), where the chip surface is periodically nanopatterned and coated with a high-refractive-index thin film to achieve guided mode resonance (GMR), are increasingly explored as label-free biosensors. This work investigates their operation beyond optical biosensing, focusing on simultaneous electrochemical and electrically assisted domains. In such platforms, the choice of coating material plays a decisive role in defining both functionality and inherent limitations. The ability to operate in multiple domains is studied here using transparent conductive oxides (TCOs) as a material example. Besides dual-domain functionality, TCOs may offer cross-domain effects, such as electro-optical modulation through free charge carrier distribution, enabling dynamic control of GMR. It has been found that, from the coating material perspective, fundamental trade-offs govern tunability, optical and electrochemical performance, and environmental robustness. This work presents a general perspective on coating material limitations in multifunctional PhC biosensors and outlines design guidelines for balancing optical and electrochemical requirements in multi-domain sensing platforms.

Laser-induced printing of structural colors is a low-cost, flexible

and rapid fabrication technique with growing industrial applications such as

anti-counterfeiting visual features. Nonetheless, the strong sensitivity of laser-

induced colors to the initial metasurface state requires high reproducibility and

challenges large-scale production. As no physical model is currently capable

of forecasting the resulting colors from the processing parameters, we propose

a machine learning based adaptive strategy to predict laser-induced colors on

weakly varying random plasmonic metasurfaces from the measurement of their

initial transmission spectrum, with the aim of improving the robustness of the

printing process. This approach is based on a contextual hypernetwork, fed by

the initial metasurface spectrum, which reconfigures the weights of a neural net-

work mapping the processing parameter set in the resulting colors. Before any

laser-printing on a new metasurface, the model is able to update its parameters

to predict the expected colors with an accuracy 10% higher than that obtained

when relying solely on previous experiments without information on the new

metasurface. This approach removes the need for extensive physical recalibra-

tion, paving the way for scalable and robust laser-induced color printing.