Phase retrieval of reflectance for nanoparticle optical identification

We present a method for optical identification of dielectric and metal nanoparticles in a liquid matrix using phase retrieval of reflectance with TE- and TM-polarized light. A formula is derived for extracting the effective complex dielectric function of a nanoparticle colloid based on different complex reflectance components. The phase retrieval is performed using the maximum entropy method. We observe excellent accuracy both for dielectric and metallic nanoparticles with volume fractions up to 10%.