ENGINEERING OF SCATTERING WAVE FROM MULTIPLE NANOSPHERES SYSTEM

• Main Author: Natanael, Misael
• Format: Final Project
• Language: Indonesia
• Subjects: Fisika
• Online Access: https://digilib.itb.ac.id/gdl/view/38191
• Institution: Institut Teknologi Bandung

Technologies which can control, manipulate and engineer a beam of light in nanoscale have been growing rapidly. Various geometrical shapes of the designed nanostructures have been investigated. One of the shapes which has interesting feature to be analysed is spherical shape. Using light scattering analysis on the structure being considered, one can manipulate the optical responses of the structure. Mie scattering theory for multiple spheres is used in this Final Project research. The theory is based on the fields expansion using vector spherical harmonics basis and addition theorem which shows interaction between the spheres. Using this formulation, the scattering, extinction, and absorption cross sections can be calculated and also multipole components (such as dipole, quadrupole, and so on) of the scattering cross section can be obtained using decomposition technique. By applying Mie formulation for multiple spheres, we design nanospheres system which can control the direction of scattered light. Using asymmetric dimer structure made of silicon (Si), directional scattering can be produced and controlled by changing the spheres configuration or incident wavelength. This phenomenon occurs due to constructive interference of multipole radiation in a specific direction. By varying one of the sphere's size, resonance wavelength is shifted and the scattering direction altered.