Nonlinear thermo-optical properties of two-layered spherical system of gold nanoparticle core and water vapor shell during initial stage of shell expansion

Nonlinear thermo-optical properties of two-layered spherical system of gold nanoparticle core and water vapor shell, created under laser heating of nanoparticle in water, were theoretically investigated. Vapor shell expansion leads to decreasing up to one to two orders of magnitude in comparison with initial values of scattering and extinction of the radiation with wavelengths 532 and 633 nm by system while shell radius is increased up to value of about two radii of nanoparticle. Subsequent increasing of shell radius more than two radii of nanoparticle leads to rise of scattering and extinction properties of system over initial values. The significant decrease of radiation scattering and extinction by system of nanoparticle-vapor shell can be used for experimental detection of the energy threshold of vapor shell formation and investigation of the first stages of its expansion

COMPARISON OF NUMERICAL-MODELS FOR COMPUTING UNDERWATER LIGHT FIELDS

Seven models for computing underwater radiances and irradiances by numerical solution of the radiative transfer equation are compared. The models are applied to the solution of several problems drawn from optical oceanography. The problems include highly absorbing and highly scattering waters, scattering by molecules and by particulates, stratified water, atmospheric effects, surface-wave effects, bottom effects, and Raman scattering. The models provide consistent output, with errors (resulting from Monte Carlo statistical fluctuations) in computed irradiances that are seldom larger, and are usually smaller, than the experimental errors made in measuring irradiances when using current oceanographic instrumentation. Computed radiances display somewhat larger errors

Detecting CDOM fluorescence using high spectrally resolved satellite data: a model study.

Absorption and fluorescence of CDOM are widely used to characterize its concentration and composition, both in situ and with remote sensing techniques. As fluorescence is an inelastic scattering process, it can potentially be observed in filling-in of Fraunhofer lines with the DOAS method in high spectrally resolved satellite data. Here, we perform a theoretical model study and preliminary DOAS retrieval on SCIAMACHY data in order to test the feasibility of such an approach. Our results show that retrieving CDOM fluorescence is difficult, due to its relatively weak signal in global oceans (in comparison to Raman scattering of clear water)and varying broad spectral features. Detailed studies of the synergistic use of narrow and broad fluorescence features, and an appropriate scheme to account for disturbance effects of Raman scattering, are needed for further investigating the retrieval of CDOM fluorescence

Phase functions as solutions of integral equations

A phase function is an important characteristic of a scattering medium. A method to derive new analytic phase functions is proposed. The relation between a phase function and an angle-averaged single-scattering intensity, derived earlier [M. L. Shendeleva, J. Opt. Soc. Am. A 30, 2169 (2013)], is considered as an integral equation for a phase function. This equation is classified as an Abel integral equation of the first kind, whose solution is known. Two phase functions newly derived with this method are presented

Circular Polarization Vision of Scarab Beetles

International audienceIn this chapter the occurrence of circularly polarized (CP) light in nature (both in the abiotic and biotic optical environment) is surveyed. We deal with the reason and the possible adaptive significance of CP light reflected from the exocuticle of many beetle species belonging to the Scarabaeoidea. This unique feature of the insect exocuticle seems to have evolved only in scarabaeoids. The imaging polarimetry of circularly polarizing scarab beetles and its results are reviewed. The alleged CP sensitivity in Chrysina gloriosa scarabs is briefly discussed. Finally, the experimental evidence for the lack of CP vision in the scarab species Anomala dubia, A. vitis (Coleoptera, Scarabaeidae, Rutelinae), Cetonia aurata, and Protaetia cuprea (Coleoptera, Scarabaeidae, Cetoniinae) with circularly polarizing exocuticle is presented