Publicaties

2-D and 3-D Raman mapping are powerful imaging techniques for creating chemical images and compositional analysis of materials. Nevertheless, integration and implementation of Raman mapping on a microfluidic system turns out to be arduous due to several challenges, including the movement of sample, low efficiency of detection, low signal-to-noise ratio, and long measurement times. This study introduces a multimodal microchip for concurrent ...

The deployment and advancement of high-bandwidth communication networks, quantum information systems, and sensing platforms relying on multi-core optical fibers (MCFs) are challenged by the scarcity of cost-effective, compact, and efficient optical interfacing components. This study introduces an unprecedented 3D-printed 1 x 4 splitter for MCFs fabricated with 2-photon polymerization-based direct laser writing. The pivotal element is a ...

The automation of spectral classification tasks has made machine learning models essential analytical tools. However, the complexity of hyperparameter tuning limits the practical use, particularly for novices. This study applies these classifiers to identify bacteria using surface-enhanced Raman spectroscopy (SERS), offering a rapid and non-invasive alternative to the gold standard, matrix-assisted laser desorption ionization time-of-flight mass ...

Hemoglobinopathies are among the most common inherited diseases worldwide, affecting approximately 7% of the global population. Despite advances in the standardization and harmonization of methods for HbA1c determination, an increasing number of hemoglobinopathies cause false HbA1c results. One of the common techniques for screening hemoglobinopathies is through high-performance liquid chromatography (HPLC) separation, followed by UV-VIS ...

We present a procedure for the design of multilevel metalenses and their fabrication with multiphoton-based direct laser writing. This work pushes this fast and versatile fabrication technique to its limits in terms of achievable feature size dimensions for the creation of compact high -numerical aperture metalenses on flat substrates and optical fiber tips. We demonstrate the design of metalenses with various numerical apertures up to 0.96, and ...

We analyze the temporal dynamics of an optically-pumped quantum well vertical external-cavity surface-emitting laser (VECSEL) with a Semiconductor Saturable Absorber Mirror (SESAM) using the time series obtained when varying the pump power. We unveil the quasiperiodic route to chaos in the system by characterizing the Fourier spectra, the attractors in phase space, and the Lyapunov exponents for each temporal behavior observed: periodicity, ...

Using an optical fiber to guide light towards a sample plane is a highly efficient and compact solution. However, because of the angular intensity distribution of the light exiting the fiber, directly aiming the fiber at a surface would create a very non-uniform irradiance profile, which is undesired in many applications. Several optical techniques exist to homogenize the light beam, but most of them require a significant amount of space. Here, ...

Milk is one of the most important dietary products thanks to its high nutritional value and economic importance, but unfortunately also among the top products facing food fraud and adulteration. Authentication of milk is therefore of high importance, motivating the development of novel sensing techniques. We present the use of broadband diffuse reflection spectroscopy (400 - 1700 nm) in combination with Linear Discriminant Analysis (LDA) to ...

Current optical design concepts and methods heavily rely on ray tracing and optimization algorithms. These methods often require extensive expertise, good intuition, and involve iterative trial-and-error workflows. We propose a novel approach that directly generates promising initial designs based on the application- and user-specific requirements and constraints. Our newly developed 'First Time Right' (FTR)-based design tool automatically ...