Seminar Announcement: Maciej Czajkowski

Announcement
Tuesday, 6 May 2025, 14:00
Sala Grande Palazzina B via alla Cascata 56/C

"Fabrication of various type periodic structures for photonic systems"

Maciej Czajkowski
Łukasiewicz Research Center – PORT Polish Center for Technology Development,
Wrocław, Poland
E-mail: maciej.czajkowski@port.lukasiewicz.gov.pl

Abstract
Photonic crystals are structures exhibiting periodicity in refractive index which results in selective colored reflection of light – so-called structural color or light diffraction properties. Due to these characteristic optical properties, they can find various applications as specific parts of photonic systems, like microresonators, waveguide couplers or filters, as well as sensors, anti-counterfeiting materials or pigments.

They can be fabricated by processing of existing materials, typically in a form of layers (top-down approach) or by self-assembly processes at molecular or submicrometer scale (bottom-up approach). Various types of photonic crystals, methods of their production used in Advanced Materials Synthesis Group from Łukasiewicz-PORT and optical properties will be presented.

Results of diffraction gratings fabrication by direct laser interference methods and nanoimprint in thin layers will be shortly described. Moreover, studies on chirally-doped liquid crystals and dye-doped liquid crystal systems with ionic liquids will be reviewed. In the second part, results on synthesis of polymeric and silica monodisperse colloidal spheres and possibilites for fabrication of 3D and 2D opals and inverse opals, showing photonic crystal properties will be presented. The spheres were doped with different luminescent dyes on the synthesis step, resulting in angle-dependent emission, due to presence of a stop-band. Finally, emulsion-based methods were used to obtain spherical symmetry photonic crystals based on colloidal spheres and cholesteric liquid crystal polymers.

All of the materials and systems presented can be modified on the fabrication step and adapted to integrate with different components of photonic systems.