Veröffentlichungen und Präsentationen

Silicon-based integrated photonics offers a versatile platform for next-generation technologies, including telecommunications, quantum information processing, and lab-on-chip systems. Photonic functionalities can be realized either on the wafer surface ("on-chip") or, more recently, within the wafer volume ("in-chip"), owing to recent developments in laser lithography techniques [1]. Combined with advanced beam-shaping methods, nanosecond laser writing enables the fabrication of nanoline arrays with widths ranging from 150 to 800 nm and tunable periods between 700 nm and 2 µm [2], providing a scalable and maskless route for engineering complex photonic architectures. Furthermore, selective wet etching of the laser-modified regions transforms the patterns into silicon–air nanostructures, substantially increasing the refractive-index contrast. The resulting high-index-contrast architectures enable stronger optical confinement and enhanced light–matter interactions, making them attractive for metasurfaces, diffractive optics, and other nanophotonic devices. In our previous work, we demonstrated high-efficiency multilevel diffraction gratings fabricated inside silicon using nanosecond laser writing [3]. Recent advances in laser nanolithography have now extended the achievable feature size from the micrometer to the nanometer scale, enabling the realization of resonant Si nanostructures that were previously inaccessible using in-chip fabrication techniques. In this work, we numerically investigate the excitation and tuning of high-Q resonances in silicon metasurfaces through intentional geometric symmetry breaking in periodic nanoline arrays. The resonant response is engineered by optimizing key structural parameters, including the lattice period, duty cycle, and the width asymmetry of the unit-cell elements, defined as α = |w1 − w2|. Figure 1 illustrates the unit-cell geometry used in the COMSOL simulations, whereas Fig. 2 presents a three-dimensional rendering of the multilevel nanoline-array architecture. We first employ the eigenfrequency solver in COMSOL Multiphysics® to determine the optimum lattice period that maximizes the quality factor at the target operating wavelength. Subsequently, the evolution of radiative leakage and Q factor is systematically analyzed as a function of the asymmetry parameter. As summarized in Table 1, our preliminary results demonstrate the emergence of multiple ultra-high-Q resonances in the vicinity of the 1550-nm telecommunications wavelength through precise control of structural asymmetry.