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Spatial coherence function (SCF) is a complex function of two spatial coordinates that, in general, carries more information than the bare intensity distribution. A fast and quantitatively accurate measurement of the SCF is extremely important for a range of applications in optical sensing and imaging. Here, we demonstrate an efficient two-step procedure for measuring the full-field complex coherence function. The measurement relies on an optimized design of a wavefront shearing interferometer capable of characterizing spatially inhomogeneous fields over an extended angular domain. The measurement precision is confirmed by the excellent agreement with a numerical estimation based on Fresnel calculations. We demonstrate that the sensitivity and the measurement range afforded by our instrument permits us to reliably describe the differences in the complex coherence functions that are due to subtle modifications in the shape, position, and orientation of radiation sources.

In classical diffraction theory, Babinet's principle relates the electromagnetic fields produced by complementary sources. This theorem was always formulated for single-point quantities, both intensities or field amplitudes, in conditions where the full spatial coherence is implicitly assumed. However, electromagnetic fields are, in general, partially coherent, and their spatial properties are described in terms of two-point field-field correlation functions. In this case, a generalized Babinet's principle can be derived that applies to the spatial coherence functions. We present both the derivation and the experimental demonstration of this generalized Babinet theorem.

The optical size and intrinsic material properties of scattering particles introduce inherent restrictions on their scattering patterns. We show that large size, core-shell dielectric structures with spherical symmetry provide the necessary flexibility for exciting higher-order spherical modes and, consequently, allow us to control the directivity of the scattered radiation. Significant scattering can be generated over angular domains that were formerly believed to be accessible only to dipolar scattering.

We demonstrate that a nonvanishing interaction force exists between pairs of induced dipoles in a random, statistically stationary electromagnetic field. This new type of optical binding force leads to long-range interaction between dipolar particles even when placed in spatially incoherent fields. We also discuss several unique features of the dipole-dipole interaction in spatially incoherent Gaussian fields.

We show that optical anisotropy can exist in composite materials even when they consist of components that are isotropic in shape, spatial distribution, and optical properties. We demonstrate that the simple presence of a surface on a metal-dielectric composite induces an optical anisotropy that manifests itself in an unusual change of the state of polarization and spin Hall effect of reflected light.

In the practice of near-field scanning probe microscopy, it is typically assumed that the distance regulation is independent of the optical signal. However, we demonstrate that these two signals are entangled due to the inherent action of optically induced force. This coupling leads to artifacts in both estimating the magnitude of optical fields and recording topographic maps.

We show that the interferometric interaction between the tip and the sample is inherently measured by a near-field scanning optical microscope (NSOM) operating in reflection mode. This is demonstrated by measuring the phase of the sample reflectivity on a standard multilayer system with variable thickness. The demonstrated intrinsic sensitivity to the phase has implications in the interpretation of images collected by using reflection mode NSOM.