FABRICATION AND CHARACTERIZATION OF SPR FROM 1-D SQUARE SUBMICRON PERIODICITY GRATING COATED WITH GOLD METAL

• Main Author: Rasyid Daelani, Abdullah
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/63222
• Institution: Institut Teknologi Bandung

The interaction between the free electrons in the metal and light causes the presence of plasmons, which causes electron delocalization. The electron delocalization condition that occurs at the boundary between the dielectric medium and the metal causes the phenomenon of electron density propagation along with the interface between the mediums which is known as the surface plasmon resonance (SPR). This phenomenon results in the absorption of light at the associated wavelength and angle of incidence. SPR is widely applied to biosensors and photonic devices. SPR absorption can be increased using SPR coupler, one of which is diffraction grating. This research has succeeded in fabricating a sub-micron size one-dimensional diffraction grating as an SPR coupler. The diffraction grating was molded to a Si template with a duty cycle of 53.33% using imprint lithography method. Furthermore, the SPR diffraction was grating was fabricated by coating gold on a diffraction grating with a thickness of 80 nm and 100 nm using thermal evaporation method. SEM measurements showed the diffraction grating pattern which corresponded to the shape of the Si mold with a duty cycle of 75.71%. SPR characterization simulation was carried out using the Rigorous Coupled-Wave Analysis method with the MATLAB program. The results of the SPR measurement using a diffraction grating coupler compared with the simulation results have errors of: 0.10% to 0.94% for 80 nm gold thickness and 1.19% to 3.92% for 100 nm gold thickness. This discrepancy is thought to occur due to the difference in duty cycle between the Si mold and the SPR diffraction grating.