O B A V I J E S T
HIRSHIKESH KAMBLE
održat će znanstveni kolokvij (doktorski seminar) iz Atomske, molekulske i optičke fizike pod naslovom:
Assisted solid state ion exchange for nanostructuring metal layers with optical losses in infrared range
Infrared optical coatings often rely on multilayer dielectric structures whose physical thickness increases with wavelength, leading to longer deposition times, higher material use, and greater mechanical and thermal stress. Highly lossy materials provide a thinner alternative because optical attenuation can be used directly rather than relying only on interference. However, intrinsically lossy infrared materials can be limited in material choice, operating spectral range, and fabrication requirements. A further approach is therefore to use metal layers in which the optical response is controlled through the morphology of the metal layer. In particular, nearly percolated metal morphologies can provide strong optical losses while maintaining a small total thickness.
This work investigates two post-deposition approaches for tuning the morphology of Ag films towards highly lossy optical behaviour in the infrared: thermally induced ion diffusion and electric-field-assisted dissolution (EFAD). Ag films deposited on dielectric-coated soda-lime glass were studied using spectroscopic ellipsometry, Raman and FTIR spectroscopy, scanning electron microscopy, secondary-ion mass spectrometry, and optical microscopy.
Thermal annealing results in a systematic evolution of the Ag layer from a compact metallic film towards discontinuous morphologies with strongly modified optical properties. The results also show simultaneous Ag and Na diffusion through the dielectric layer, with the Na content of the glass influencing the rate of optical evolution. Electric-field treatment was further studied for SiO₂, TiO₂, Nb₂O₅ and Y₂O₃ layers, revealing material-dependent structural responses ranging from local bond rearrangement and stress-related cracking to crystallisation of TiO₂ to anatase. EFAD of Ag films deposited on SiO₂ and TiO₂ coated soda-lime glass also resulted in highly lossy effective optical responses; however, reproducible control is presently limited by variations in current (I) and lateral non-uniformity of the treated samples.
Overall, the results show that thermally induced diffusion and EFAD can be used as post-deposition routes for modifying the optical response of thin Ag-based structures in the infrared, while also identifying the role of the dielectric layer and the experimental limitations that must be addressed for reliable EFAD control.
Seminar će se održati u srijedu, 23. rujna 2026. godine u 10:00 sati u predavaonici F-201 Fizičkog odsjeka Prirodoslovno-matematičkog fakulteta Sveučilišta u Zagrebu.
Pozivaju se studenti doktorskog studija Fizike, smjer Atomska, molekulska i optička fizika, da prisustvuju seminaru, ako nisu spriječeni.
Voditelj smjera:
Prof. dr. sc. Hrvoje Buljan, v.r.
Pristupačnost
