Coherence properties near interfaces of random media

Abstract

The spatial coherence theory of optical fields radiated by statistically homogeneous, infinite, planar sources does not account for detailed surface characteristics. However, coherence properties change with the angular distribution of the intensity radiated from such a source, which, in turn, depends on the physical properties of the sample. We show that second-order correlations of the optical field measured at several wavelengths away from the surface of a highly inhomogeneous medium relate to the statistical characteristics of the interface.

Wide-Field Super-Resolution Optical Fluctuation Imaging through Dynamic Near-Field Speckle Illumination

“…To eliminate this spurious correlation for acquiring full resolution benefit of the SOFI algorithm, the grain size of illuminating speckle patterns should be much smaller than the diffraction limit, as shown in Figure b, to realize mutually independent flickering of individual fluorophores. This subwavelength grain size is the unique feature of the near-field speckle patterns − and opens an opportunity to break the resolution limit of (far-field) S-SOFI technique by approximating the speckle-fluctuated fluorescence to intrinsic blinking of the individual fluorescent labels.…”

“…The actual correlation length can be even smaller than the measured value (150 nm), since no correction is applied to take into account of additional blur caused by the finite aperture size of the NSOM tip (see Section S1 in the Supporting Information). This sub-wavelength-scale grain size is the unique feature of near-field speckle patterns whose correlation length is driven by the microstructure of the scattering medium, not by the wavelength of the scattered light. − Unlike far-field speckle illumination with complex field exhibiting Rayleigh statistics, although dynamic near-field speckle illumination employed for NS-SOFI deviates from Rayleigh statistics (see Figure S2.2 in the Supporting Information), − the intensity statistics of speckle illumination that directly translates to the final super-resolution is the grain size, not the type of the speckle field statistics.…”

“…Introducing dynamic near-field speckle illumination − in S-SOFI endows new opportunities to realize a novel mode of wide-field subwavelength imaging. Subwavelength grain size of near-field speckle patterns increases the chances that fluorescent emitters separated even within subdiffraction distance experience different excitation intensity, well-approximating intrinsic blinking of the individual emitters, which is a crucial assumption to realize full resolution gain granted by SOFI processing .…”

Statistical properties of spontaneous emission from atoms near a rough surface

“…Here, we are interested in some recent results relevant for our system. It has been shown recently that the intensity correlations above random media or materials with rough surfaces become non universal in the near field, i.e., they highly depend on the properties of the random media or rough surfaces [14][15][16][32][33][34].…”

“…The lifetime of an atom or molecule becomes a random quantity which depends on the local environment of the particle and the statistical properties of the surface. Recently, the speckle pattern above random media [15][16][17] has been studied. The goal of this work is to reconsider the impact of surface roughness on the spontaneous decay rate.…”