Light Scattering and Photon Correlation Spectroscopy, 1997 NATO Science Partnership Subseries: 3 Series, Vol. 40

Since their inception more than 2.5 years ago, photon correlation techniques for the spatial, temporal or spectral analysis of fluctuating light fields have found an ever-widening range of applications. Using detectors which re­ spond to single quanta of the radiation field, these methods are intrinsically digital in natnre and in many experimental situations offer a unique degree of accuracy and sensitivity, not only for the study of primary light sources themselves, but most particularly in the use of a laser-beam probe to study light scattering from pure fluids, macromolecular suspensions and laminar or turbulent flowing fluids and gases. Following the earliest developments in laser scattering by dilute macro­ nl01ecular suspensions, in , ... hich particle sizing was the main aim, and the use of photon correlation techniques for laser-Doppler studies of flow and tnrbuence. both of which areas were the subject of NATO ASls in Capri, Italy in 19;:3 and 19;6. significant advances have be('n made in recent years in many other areas. These were reflected in the topics covered in this NATO Advanced Research Workshop, which took place from August 2;th to 30th, 1!)!}6, at the Jagiellonian University, Krakow, Poland. These in­ cluded ('xperimental techniques. statist.ics and data reduction, colloids and aggregation, polymers, gels, liquid crystals and mixtures, protein solutions, critical pllf'nomena and dense media.

Colloids.- Experimental challenges in colloids.- Dynamic depolarized light scattering studies of anisotropic Brownian particles.- Application of the dynamic light scattering method for investigation of colloidal stability.- Long-time dynamics of concentrated colloidal suspensions.- Methods.- Suppression of multiple scattering using a single beam cross-correlation method.- Theory of multiple scattering suppression in cross-correlated light scattering employing a single laser beam.- X-ray photon correlation spectroscopy.- Polarisation fluctuations in radiation scattered by small particles.- Surface light scattering spectroscopy.- Non-linearity of APDs at high count rates.- From speckles to modes: principles and applications of fiber optic dynamic light scattering..- Polymers, Gels, Liquid Crystals, Mixtures.- Photon correlation spectroscopy of interactive polymer systems.- Local dynamics in branched polymers.- Spontaneous domain growth in the one-phase region of a gel/mixture system.- The shape, dimension and organisation of maltodextrins gel fragments with and without associated phospholipids.- Dynamic light scattering from block copolymers.- Particle diffusion and crystallisation in suspensions of hard spheres.- Use of light scattering to characterize the polysaccharides of starch.- Statistics and Data Processing.- Spatial photon correlation and statistics of nonlinear processes in nonlinear waveguides.- Photon correlation of correlated photons: experimental aspects of quantum cryptography and computation.- New opto-electronic technologies for photon correlation experiments.- Correlated, superposed and squeezed vibrational states.- Structure and properties of linear inverse problems.- New ideas in data. inversion in photon correlation spectroscopy.- Tempest in a teapot-surface and volume turbulence in a closed system.- Scattering by Dense Media.- Diffusing photon correlation.- Photon correlation spectroscopy of opaque fluids.- Scattering of light in inhomogeneous medium.- Observation of shear-induced gelation using light scattering imaging.- Single particle motion of hard-sphere-like polymer micronetwork colloids up to the colloid glass transition.- Measurement of viscoelasticity of complex fluids by diffusing-wave spectroscopy.- Space Applications.- Applying photon correlation spectroscopy in space.- IIard spheres in space: light scattering from colloidal crystals in microgravity.- Zeno: Critical fluid light scattering in microgravity.- Phase Separation and Critical Phenomena.- Static and dynamic light scattering in phase-separating systems.- Shear induced displacement of the spinodal, and spinodal demixing kinetics under shear.- Spectral kinetic and correlation characteristics of inhomogeneous mixtures in the vicinity of the critical point of stratification.- List of participants.

The miniaturisation and performance improvements provided by solid state lasers, fibre optics and avalanche photodiode detectors have given a significant impulse to the use of photon correlation techniques in the study of laser scattering by macromolecular suspensions, liquid surfaces, critical fluids and turbulent liquids. The improvements can be found in experimental technique, colloids and aggregation, polymers, gels, liquid crystals and mixtures, protein solutions and dense media. Powerful new methods of inverse problems are being applied to data analysis. Much progress is being made in the study of dense media using index matching techniques. two colour systems and the theory of photon diffusion. Other notable recent developments are phase transitions in the space shuttle microgravity