| Abstract [eng] |
Formation of Nanohole Arrays in Gold Film and Investigation of Their Plasmonic Properties Extraordinary optical transmission is a phenomenon when the flux of photons per unit area emerging from the hole is larger than the incident flux per unit area. It is observed in thin metal films, perforated with nanohole arrays. When incident light interacts with free electrons in the surface of metal, surface plasmons are formed, which are responsible for extraordinary optical transmission in nanohole arrays. Due to these properties, metal nanohole arrays can be applied to many fields. Most of the applications are based on surface plasmon coupling with matter. For more proper applications, these interactions should first be better understood. The main goalof this work is to investigate the coupling between the surface plasmons in ordered and disordered nanohole arrays and single walled carbon nanotubes. Ordered and disordered nanohole arrays were fabricated by colloidal lithography and characterized using atomic force microscopy and scanning electron microscopy. Optical properties of these structures were investigated by measuring optical transmittance. For investigation of coupling between surface plasmons in nanohole arrays and carbon nanotubes, a thin layer of carbon nanotubes was formed over each of nanohole arrays. Optical transmittance and transient absorption of samples were measured. The strongest extraordinary optical transmission of the disordered nanohole arrays was observed for an array with homogeneously dispersed nanoholes with average distances between holes 500 ± 40 nm. The intensity and position of this peak is influenced by homogeneity of the nanohole array and the distances between holes. Optical transmittance and transient absorption measurements of ordered nanohole array with carbon nanotube film suggested that the coupling between surface plasmons in ordered gold nanohole array and carbon nanotubes is very weak. This may be due to only partial spectral overlap of the extraordinary transmission peak and absorbance of carbon nanotubes. Optical transmittance and transient absorption measurements of disordered nanohole array with carbon nanotube film showed strong coupling between surface plasmons and carbon nanotubes. This coupling was found to be dependent on the concentration of carbon nanotubes. Further research should be carried out to be able to fully understand the coupling mechanics between surface plasmons in ordered and disordered nanohole arrays and carbon nanotubes. |
