Electrically-controlled dynamic optical component comprising a metasurface

An optical component (1) comprising a planar metasurface (2) arranged on a surface of a first substrate (3) and a top layer (4) arranged in a height direction Z above the metasurface (2), wherein the metasurface (2) comprises an array (9) of scattering structures (5, 5a, 5b) comprising a metal, wherein the array (9) is a repeating pattern of unit cells (7), wherein a unit cell (7) comprises at least two different scattering structures (5, 5a, 5b),

• characterized in that
• the optical properties of the metasurface (2) are controllable by a control signal, wherein first scattering structures (5a) are at least partially contacting a layer of a first substance (6a) comprising a dielectric material and having a first refractive index and second scattering structures (5b) are at least partially contacting a layer of a second substance (6b) comprising a polymer, which differs from the first substance (6a) and which provides a variable refractive index depending on the control signal, wherein the real part n and/or the imaginary part K of the variable refractive index of the second substance (6b) is shiftable by the control signal to the respective value of the first sub-stance.

The optical component (1) according to one of the previous claims,

• characterized in that
• the metal of the scattering structures (5, 5a, 5b) is selected from a group comprising ruthenium, rhodium, palladium, silver, osmium, iridium, platinum, rhenium, copper and gold, wherein the scattering structures (5, 5a, 5b) preferably mainly consist of one or more of these metals, wherein the scattering structures (5, 5a, 5b) preferably comprise at least 95%, preferably ≥98%, more preferably ≥99%, most preferably ≥99.5% of one of these metals, preferably gold.

The optical component (1) according to one of the previous claims,

• characterized in that
• the scattering structures (5, 5a, 5b) are deployed as optical antennas, preferably in the form of rods, which are preferably orientated in the plane of the metasurface (2), more preferably in spatially varying orientations.

The optical component (1) according to one of the previous claims,

• characterized in that
• a geometry and size of the first and/or second scattering structures (5, 5a, 5b) in an array differs by ≤5%, preferably ≤3%, more preferably ≤1% and is most preferably the same, wherein the dimensions of the scattering structures (5, 5a, 5b) are preferably smaller than the wavelength λ of an incident electromagnetic radiation to be manipulated by the optical component, and/or wherein the spacing between the scattering structures (5, 5a, 5b) is preferably smaller than half of the wavelength λ of the incident electromagnetic radiation to be manipulated by the optical component (1).

The optical component (1) according to one of the previous claims,

• characterized in that
• the optical properties of the metasurface (2) are switchable from a first optical proper-ty to a second optical property in less than 500 ms, preferably ≤250 ms, preferably ≤100 ms, more preferably ≤50 ms, most preferably ≤35 ms.

The optical component (1) according to one of the previous claims,

• characterized in that
• a height of a volume between the first substrate (3) and the top layer (4) is at least 3×, preferably ≥5×, more preferably ≥10×, more preferably ≥20×, most preferably ≥50× the height of the scattering structures (5, 5a, 5b), wherein a medium, preferably a liquid medium, more preferably a conducting medium, most preferably an ionic solution is arranged in this volume.

The optical component (1) according to one the previous claims,

• characterized in that
• the first substance (6a) comprises a dielectric polymer, more preferably a acrylate polymer, most preferably polymethyl methacrylate, and is preferably at least partially enclosing the first scattering structures (5, 5a), more preferably contacting the first scattering structures (5, 5a) at all sides which are not contacting the first substrate (3).

The optical component (1) according to one of the previous claims,

• characterized in that
• the first and/or second scattering structures (5, 5a, 5b) provide a geometry of a cylinder or a parallelepiped, preferably a geometry of a right circular cylinder or a rectangular cuboid, wherein a longitudinal extension is preferably in the range of 100-400 nm, preferably 150-300 nm, more preferably 175-225 nm, most preferably about 200 nm, and a width extension perpendicular to the longitudinal direction in the range of 10-200 nm, preferably 20-150 nm, more preferably 30-100 nm, most preferably 50-80 nm, wherein two width extensions of a cuboid or irregular cylindrical could be independently selected from these preferred ranges.

The optical component (1) according to one of the previous claims,

• characterized in that
• each unit cell (7) comprises a line (8a) of first scattering structures (5a) and a line (8b) of the second scattering structures (5b), wherein neighboring unit cells (7) are arranged with respect to each other in such a way, that the first and second scattering structures (5, 5a, 5b) are forming in alternating lines (8a, 8b) in the array (9).

The optical component (1) according to one of the previous claims,

• characterized in that
• the first substrate (3) comprises a carrier, preferably comprising silica, more preferably comprising quartz, most preferably consisting of quartz, which is coated with a conductive coating, preferably a metal containing, most preferably an indium tin oxide coating.

The optical component (1) according to one of the previous claims,

• characterized in that
• each unit cell (7) is addressable independently by the control signal (11).

An optical device comprising the optical component (1) according to one of the previous claims, wherein an application of an electric field causes a modulation of an optical functionality of the optical device due to a modulated phase profile of an incident electromagnetic radiation, which is transmitted through or reflected by the optical component (1).