Photon Localization and Electromagnetic Field Enhancement in Laser-irradiated, Random Porous Media
نویسندگان
چکیده
By solving Maxwell’s equations, we observed photon localization and strong electromagnetic field enhancement in laser-irradiated, one-dimensional random multilayer and twodimensional random media, with particle size around the laser wavelength. Higher refractive index contrast and degree of randomness result in stronger localization. The probability density and the location of enhanced fields are investigated as functions of refractive index and particle size distribution. For weakly dissipative media, local absorption enhancement is observed, and the expectation intensity distribution is obtained by averaging among many realizations. For comparison, the equation of radiative transfer (ERT) is also solved for random porous media, using the two-flux model. Since no interference effects are allowed, the classical diffusion, rather than localization, is predicted. Consequently, ERT can represent a good statistical average of the intensities only as absorption is dominant over localization. As expected, the particle treatment of ERT does not allow for predicting photon localization and field enhancement.
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