New values of the light scattering depolarization and anisotropy of water

Abstract

A new value for the depolarization ratio of pure water has been measured at 514.5 nm using an argon ion laser light source and photon counting detection. This depolarization ratio is lower than any previous literature value by a substantial amount. Stray light and photometer geometry are shown to be responsible for overestimated values reported previously. The depolarization ratio is also shown to be a function of the portion of the spectrum being investigated. With no filters we find ρv=0.026. The magnitude of error due to finite acceptance angle is calculated and shown to be substantial. Depolarization ratios using 0.46 and 22.5 nm filters (half-peak bandwidth) are reported.

Optical backscattering properties of the "clearest" natural waters

“…It was also necessary in these extremely clear waters that the ambient water temperature be used in the computation of b bw to achieve the most accurate results. These results support the use of δ=0.051 after Farinato and Roswell (1976). However, since Farinato and Roswell is a single study that lowered a previously accepted constant (Morel, 1974;Shifrin, 1988) by more than 40%, this is certainly a topic that could benefit from additional investigation.…”

“…However, since Farinato and Roswell is a single study that lowered a previously accepted constant (Morel, 1974;Shifrin, 1988) by more than 40%, this is certainly a topic that could benefit from additional investigation. In fact, Jonasz and Fournier (2007) have recently recommended the use of δ=0.039 based on another interpretation of the data of Farinato and Roswell (1976), highlighting the substantial uncertainty that remains in this constant.…”

“…Without belaboring the details of the precise differences in the parameters where it is possible to directly compare, a general summarization may be reached that the expressions compiled by Buiteveld et al (1994) appear to be the most current in the literature (or are at least very close), as might be expected since their work is the most recent. In particular, Buiteveld et al (1994) use a δ value of 0.051 based on the work of Farinato and Roswell (1976), who claim that the much higher values previously found in the literature were the result of stray light contamination and photometer geometry errors. Their newer values were also closer to a theoretical estimate.…”

Relationships between the surface concentration of particulate organic carbon and optical properties in the eastern South Pacific and eastern Atlantic Oceans

“…The lower values of δ result in lower estimates of scattering (e.g., Jonasz and Fournier, 2007;Twardowski et al, 2007). On the basis of the study by Farinato and Roswell (1975), Jonasz and Fournier (2007) suggested that an adequate value of δ may be as low as 0.039. The theoretical estimates for lower values of δ were also shown to be closer to the experimental estimates of pure water scattering reported in Morel (1974).…”

Spectroscopic study of light scattering in linear alkylbenzene for liquid scintillator neutrino detectors

“…From Table 1, the depolarization ratios of 405, 430 and 457.9 nm for LAB are the same within 1 σ . It is well known that the depolarization ratio is a weak function of wavelength over the visible range [20,23]. Therefore, we can conclude that the depolarized part of light scattering in LAB is Rayleigh scattering even if we can not directly study the depolarization of light scattering of LAB at 430 nm, the main region of interest, due to the limitation of light source.…”