Scientific Results

IDEAS project results
"Study of deterministic nanostructuring methodes"

SEM image of a glass surface covered by a monodisperse silica spheres with 650 nm diametre. Self-organized monolayer of colloidal particles were deposit on different substrates using monodisperse silica (SiO2) and polystyrene PS spheres array as a template. Monodisperse silica or polystyrene spheres with diameters in the range of 350 nm to 1.5 nm were used. Hexagonally closed-packed colloidal monolayers are directly prepared onto the surface by spin-coating or a self-organizing process.

Principle of near-field laser ablation. The monolayers of colloidal particles deposit on a thin film are illuminated by fast and ultrafast laser pulse. After illumination of nanospheres, nanoholes arrays will be created due to the near-field effect in laser–nanosphere interactions.

SEM image of a surface pattern on a glass sample and gold film. The near-field optical engancement is responsible for surface pattern formation. Nanoholes are created by ablation.

Direct laser writing (TPP) on photopolimers was used for creating masks for ablation by near-field optical enhancement. This masks are produced on SU8 photorezist by two-photon photopolimerization technique (TPP).

The sketch of TPP technique When a femtosecond laser is focused in the volume of a negative photoresist such as SU-8, Ormocer, etc. , the two-photon absorption efect will induce the photopolimerization of the material only in a small volume at the focused spot. By translating the sample in XYZ, practicaly any 3D geometry can by reproduced from a computed design.

DLW workstation for TPP. For TPP experiments the in-house built workstation was coupled with a femtoscond oscillator SynergyPro (Femtolaser). Depending on the desired resolution or high-aspect ratio structure, the focusing optics can be chosen between a Zeiss NA 1.4 and 100x immersion oil microscope objective, or a Mitutoyo NA 0.5 and 100x microscope objective. The translation stage is a Thorlabs NanoCube with XYZ piezo stages and steppers.

Structures obtained in SU8 by TPP