Nanophotonics

Nanophotonics 1. For gold nanoparticles with a radius of 30 nm, find the extinction cross section using the dipole mode and published values for the dielectric function. Calculate for particles in air (n=1), water (n=1.33) and glycerol (n=1.473). For Au material properties see: Johnson and Christy, Phys. Rev. B, 6, 4370 (1972) or Ecthegoin, et al., J. Chem. Phys. 125, 164705 (2006). 2. Show size dependence of the extinction cross section as the Au NPs get smaller than 30 nm. Use Au NPs with radii of 5, 10, 15, 20, 25 and 30nm. Use the full Drude model with the collision damping term using vF = electron Fermi velocity = 1.4 E 6 m/s, A = 5 and ?Bulk = 1/(9.3 fs). Assume the plasma wavelength is 300 nm and the NPs are in water. Plot the normalized scattering coefficient for each size. 3. From the Kelly paper (Kelly et al., J. Phys. Chem. B 107, 668 (2003)), find the expression for the extinction efficiency including both the dipole and quadrapole terms. Hint #1: use equation 9 in the paper. Hint #2: you have the expression for the dipole mode only from class. 4. Use the result from problem 3 to graph the extinction efficiency for particles with radii of 30, 60, 120, 200, and 300 nm. Assume the particles are in water and use the dielectric function from problem 1.