Light intensity and its fluctuations on a layered microsphere: Effects of shell thickness acting as a quantum well

The present study is an extension of the former research where a double-layer microsphere is irradiated by monochromatic unpolarized plane light. One can realize intensity fluctuations on the particle surface by the numerical boundary element method. The effect of the shell thickness is primarily investigated in the present study. A refractive index reflects its potential energy photons experience in a domain. The potential energies in the air, shell, and core are different from one another with the smallest in the shell. As the shell thickness reduces, the shell layer behaves like a quantum well after a critical thickness. The resultant light intensities on the particle surface show noise-like fluctuations depending on such parameters as the shell thickness, the light wavelength, the particle size, etc. Noticeable fluctuations appeared with the shell thicknesses less than around 5 nm. The thinner the shell, the stronger the intensity fluctuations, suggesting the more light absorbing ability. More efficient photon energy absorption observed with quantum well optoelectronic devices should be explained by stronger intensity fluctuations, not by higher intensities ensuing from photon confinement in quantum wells.