Black carbon (BC) is an important light absorber (Bond & Bergstrom, 2006). Its optical properties are complicated by the complex particle morphology, such as the non-sphericity of the refractory BC (rBC) core (China et al., 2013), the amount of non-BC associated with it (termed as coatings) (Moffet & Prather, 2009;Zhang et al., 2008), and how the coatings and rBC components are combined (Liu et al., 2017). The conventional Mie calculation with the assumption of a core-shell structure may only apply to largely coated BC (Liu et al., 2017). However, it may exhibit a range of diversities when the amounts of coatings are not substantially higher than rBC (Fierce et al., 2020). The particle morphology of BC can be modified during aging (Akagi et al., 2012; and importantly determines the optimum optical models to be used (He, 2019). The inclusion of particle-resolved heterogeneity in the mixing state could induce an uncertainty of 30% in modeling the absorbing properties of BC (Fierce et al., 2016).The shape of non-spherical particles has been extensively studied based on the rule that a more irregular shape of a particle exerts a higher drag force than a sphere in an electric field, and a dynamic shape factor (χ) can be obtained by the ratio of the drag force on a non-spherical particle to its volume-equivalent sphere (Hinds, 1999). This is introduced to describe the particle shape in the form of electric mobility size

The reconfigurable metasurface (MS) with tunable electromagnetic scattering properties has had an impact on innovative communication applications. However, the widely studied MS controlled by direct-current (DC) bias requires complex physical control circuits in array wavefront encoding, while the light-controlledapproach of the light-controlled MS MSwith a controlladoes not. In this paper, we report a newble modulation range of reflection phase,and its unit is composed of a reflection phase element based on the varactor and an opticalinterrogation network (OIN) based on the photoresistor so that the phase distribution of eachMS unit could be independently programmed optically. To illustrate our approach, a 2-bit reflection phase MS with 10 × 10 units was fabricated and tested to achieve pencil beam scanning and orbital angular momentum (OAM) beam at microwave frequencies. The simulated and measured results verify the feasibility of the proposed design. Furthermore, all the OINs on the MS are connected in parallel and powered by the same DC voltage source, which simplifies the difficulty of array expansion in MS design with a large-scale array.

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