Electrodeposited zinc oxide arrays with the moth-eye effect

Fully carbon metasurface: Absorbing coating in microwaves

“…Hence the calculations can be significantly simplified by applying a homogenisation procedure to the given structure and using the long-wave approximation. This methodology is traditionally used in optics for modelling antireflective coatings 30,32 , and was successfully applied in our recent works 12,27 . It is important to note that the primitive homogenisation used in 12 for a monolayer of hollow spheres, consisting in averaging non-conductive air regions with highly conductive carbon regions according to their relative volume fractions, was not successful in describing the experimental data in the case of the present porous spheres.…”

“…Moreover, nonhomogeneous structures with graded refractive index are widely used in the industry for designing and developing various types of microwave absorbers [24][25][26][27][28][29] and the long-wave approximation [30][31][32][33] is commonly applied to describe and predict their electromagnetic properties in the microwave frequency range.…”

Effect of Nanograin Sublayers on Structure and Properties of the Electrodeposited ZnO Arrays

“…The reason is not only in the unique properties of this wide bandgap semiconductor (Eg = 3.37 eV) with direct optical transitions and a large exciton binding energy (60 MeV at the room temperature), but also in the possibility of obtaining ZnO using different technologies, including inexpensive and suitable for large-scale production of liquid-phase chemical and electrochemical methods [2][3][4][5][6][7][8][9][10] . The another advantage of the material ZnO is its propensity to form nanostructures with different morphology among which the greatest interest for the developers of electronic products and optoelectronics attract nanowires and nanorods, i.e., one-dimensional (1-D) nanostructures of zinc oxide.…”

Hollow carbon spheres in microwaves: Bio inspired absorbing coating

“…Its structure is similar to a well-known type of anti-reflective surfaces having a "moth-eye"-like structures. [8][9][10] In the present case, however, the HS monolayer is an electrically conductive material with losses; thus, due to these attractive properties, it may be used for EM absorption applications. With this aim in view, the long-wave approximation, used for modelling structures presenting a spatial dispersion of refractive index, 9 was adapted to the description of the HS monolayer response in microwaves.…”

“…This allowed to apply long-wave approximation widely used in optics for modelling antireflective coatings. [8][9][10] This approximation allows introducing a homogenisation procedure to calculate the spatial dispersion of the effective refractive index of the monolayer formed by the 2D packed lattice of spheres (see below). Therefore, the investigated system can be considered as a stack of thin layers of constant refractive index so that the characteristic matrix of the corresponding assembly of thin films can be calculated and directly converted into reflection R ¼ S 2 11 and transmission T ¼ S 2 21 coefficients.…”