Figure 2.

(A) A color photograph of a collection of colloidal particles illuminated with a white light source. The area imaged is 24 × 24 μm. The particles were prepared such that their plasmon resonance peak wavelength is at ≈440 nm. (B) A three-dimensional–perspective CCD image of the intensity of light scattered by a single PRP. (C) The intensity of light measured along a line of CCD pixels passing through the maximum value of the image presented in B. Because the PRPs are subwavelength in size, the image of B is nearly that of a point source, i.e., the point spread function of the optical system. The deviations from circular symmetry are caused by asymmetry and aberrations in the objective lens.