Light Scattering investigation of Black Turmeric (Curcuma caesia): a comparative study with established Mie theory

Abstract

This study reports measurements of the angular distribution of the scattering matrix elements $d_{11}$ and $d_{12}$ for randomly oriented sub-micron Black turmeric (Curcuma caesia) particles using a light scattering technique with a He–Ne laser at 632.8 nm. The volume scattering function and depolarization effects were experimentally investigated at room temperature (25$^\circ$C). Theoretical predictions of $d_{11}$ and $d_{12}$ were obtained using Philip Laven’s software, based on Mie theory, which describes light scattering by spherical or randomly oriented non-spherical particles. A significant deviation was observed between experimental results and theoretical profiles, indicating the strong influence of particle size, shape, and their distributions on scattering behavior. Given the organic nature of Black Turmeric, external factors such as temperature, humidity, and moisture can further alter scattering characteristics. While experiments can be extended to different temperatures, theoretical modeling remains restricted, as widely used light scattering codes do not account for temperature effects or distributions in size and shape. These findings highlight both the practical importance of experimental investigation for organic samples and the limitations of Mie theory in fully capturing the scattering behavior of Black Turmeric particles under varying conditions.