Optical Super Surface Film

Abstract

An optical metasurface film, comprising: a flexible polymer film having a first major surface; a patterned polymer layer having a first surface adjacent to the first major surface of the flexible polymer film and having a second nanostructured surface opposite to the first surface; and a refractive index contrast layer adjacent to the nanostructured surface of the patterned polymer layer, thereby forming a nanostructured bilayer with a nanostructured interface. The nanostructured bilayer locally acts on the amplitude, phase or polarization of light or a combination thereof, and applies an optical phase shift that varies with the position of the nanostructured bilayer on the flexible polymer film. The optical phase shift of the nanostructured bilayer defines a predetermined operating phase distribution of the optical metasurface film.

Description

Background Art

[0001] Metamaterials are synthetic composite materials with nanoscale features on at least one surface. When the nanoscale features are selected to have at least one dimension that is smaller than the wavelength of light impinging on the surface, metamaterials can exhibit properties that are not easily obtained using conventional materials and techniques. Metamaterials can have simple surface structures, such as a single or a small number of patterned layers, or more complex surface structures, such as stacked patterned layers that are generally aligned to each other so that the individual nanoscale features interact electromagnetically with the impinging radiation according to their design. Metamaterials with a single or a small number of patterned layers are called metasurfaces. Metasurfaces with nanoscale surface features have recently found applications in optics, biosensing, semiconductors, and other electronic devices.

[0002] For example, metasurfaces have been formed on rigid surfaces using electron beam lithography and atomic layer deposition. These materials have been formed on substrates with limited surface area. These materials have been formed on wafer substrates with a diameter of 300 mm or less.

[0003] There are two main types of metasurfaces: geometric phase metasurfaces and propagation phase metasurfaces. Geometric phase metasurfaces induce optical phase shifts via spatially rotated identical nanostructures, where each individual nanostructure acts as a half-wave plate. Propagation phase metasurfaces induce optical phase shifts using linear birefringent nanostructures with different lateral dimensions at each spatial position. These two approaches can also be used in combination. Summary of the invention

[0004] Optical metasurface polymer films are described. These optical metasurface polymer films can be formed on flexible substrates. The flexible substrate can be a large-format substrate with a lateral dimension greater than 300 mm, for example. These optical metasurface polymer films can be formed using roll-to-roll processing with high fidelity.

[0005] An optical metasurface film, comprising: a flexible polymer film having a first major surface; a patterned polymer layer, the patterned polymer layer having a first surface adjacent to the first major surface of the flexible polymer film and having a second nanostructure surface opposite to the first surface; and a refractive index contrast layer, the refractive index contrast layer comprising a refractive index contrast material adjacent to the nanostructure surface of the patterned polymer layer, thereby forming a nanostructured bilayer with a nanostructured interface. The nanostructured bilayer locally acts on the amplitude, phase or polarization of light or a combination thereof, and applies an optical phase shift that varies with the position of the nanostructured bilayer on the flexible polymer film. The optical phase shift of the nanostructured bilayer defines a predetermined operating phase distribution of the optical metasurface film.

[0006] The nanostructured bilayer can locally act on the amplitude of light. The nanostructured bilayer can locally act on the phase of light. The nanostructured bilayer can locally act on the polarization of light.

[0007] The nanostructured bilayer may be defined by a solid material. The nanostructured bilayer may be formed of a solid material. The nanostructured bilayer may be formed of a polymeric material.

[0008] The nanostructured bilayer may further include an etch stop layer separating the patterned polymer layer from the first major surface of the flexible polymer film.

[0009] The refractive index contrast material may have a first refractive index value and the patterned polymer layer has a second refractive index value that differs from the first refractive index value by at least 0.25, or by 0.5, or by 0.75, or by 1.0, or by 1.4.

[0010] The nanostructured bilayer may be defined by a plurality of nanostructures embedded in a refractive index contrast layer. The aspect ratio of the nanostructures forming the nanostructured surface may be at least about 1:1, 2:1, 5:1, 10:1, or 15:1. The nanostructures forming the nanostructured surface preferably have an aspect ratio in the range of about 2:1 to about 20:1, or about 4:1 to about 15:1.

[0011] The nanostructures forming the nanostructure surface may define a tapered sidewall having an angle in the range of about 1 to 10 degrees, 2 to 10 degrees, 3 to 10 degrees, 4 to 10 degrees, 1 to 6 degrees, 2 to 6 degrees, or 3 to 6 degrees, or 2 to 4 degrees. The nanostructures forming the nanostructure surface may define a tapered sidewall having an angle in the range of about 0 to 10 degrees, 0 to 6 degrees, 0 to 3 degrees, 0 to 2 degrees, 0 to 1 degree, or 0 degrees.

[0012] The refractive index contrast material may include a metal oxide or a metal nitride. The refractive index contrast material may include at least one of titanium, zirconium, tantalum, hafnium, niobium, zinc, or cerium; an oxide of titanium, zirconium, tantalum, hafnium, niobium, zinc, or cerium; a nitride of titanium, zirconium, tantalum, hafnium, niobium, zinc, or cerium; a sulfide of titanium, zirconium, tantalum, hafnium, niobium, zinc, or cerium; or a combination thereof.

[0013] The patterned polymer layer may include a fluorinated polymer, a (meth)acrylate (co)polymer, or a silicon dioxide-containing polymer. The patterned polymer layer may include a fluorinated acrylate, and the refractive index contrast material may include titanium dioxide. The patterned polymer layer may include a (meth)acrylate, and the refractive index contrast material may include titanium dioxide.

[0014] The average thickness of the flexible polymer film may be in the range of about 5 microns to about 300 microns. The height of the nanostructures forming the nanostructured surface may be 5 microns or less, or in the range of about 100 nanometers to about 3000 nanometers, or about 500 nanometers to about 1500 nanometers.

[0015] The nanostructures forming the nanostructured surface have an average spacing (center-to-center distance between adjacent nanostructures) that is a sub-wavelength relative to the shortest wavelength contained in the interrogating electromagnetic radiation. For optical metasurfaces operating in the visible spectrum, the average spacing of the nanostructures forming the nanostructured surface may be 600 nanometers or less, or 500 nanometers or less, or 400 nanometers or less. For optical metasurfaces operating in the visible spectrum, the average spacing of the nanostructures forming the nanostructured surface may preferably be 50 nanometers to 600 nanometers, or 100 nanometers to 500 nanometers, or 200 nanometers to 400 nanometers.

[0016] The nanostructures forming the nanostructured surface are spaced apart by a sub-wavelength lateral distance. The nanostructures forming the nanostructured surface are spaced apart by about 400 nanometers or less, or between about 20 nanometers and about 400 nanometers, or between about 50 nanometers and about 300 nanometers.

[0017] The nanostructures forming the nanostructured surface have a lateral dimension orthogonal to the nanostructured feature height, which is sub-wavelength. The nanostructures forming the nanostructured surface may have a lateral dimension orthogonal to the nanostructured feature height, which is about 600 nanometers or less or in the range of about 10 nanometers to about 400 nanometers, or in the range of about 50 nanometers to about 350 nanometers.

[0018] Optical phase shift can occur in the visible wavelength range. Optical phase shift can occur in the near IR wavelength range. Optical metasurface films can transmit visible light or near infrared light.

[0019] In the case of a geometric phase metasurface, the nanostructures forming the nanostructured surface may have different orientations, depending on the position of each nanostructure on the flexible polymer film. The nanostructures forming the nanostructured surface may have different spatial arrangements, depending on the position of each nanostructure on the flexible polymer film. In the case of a propagation phase metasurface, the nanostructures forming the nanostructured surface may have different shapes, depending on the position of each nanostructure on the flexible polymer film. The nanostructures forming the nanostructured surface may have different aspect ratios, depending on the position of each nanostructure on the flexible polymer film.

[0020] The nanostructures forming the nanostructure surface may be geometrically anisotropic in the planar direction. The nanostructures forming the nanostructure surface may be geometrically isotropic in the planar direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic cross-sectional view of an exemplary optical metasurface film.

[0022] Figure 2 Schematic top-down elevation views of four representative optical metasurface films are shown.

[0023] Figure 3 A cross-sectional schematic diagram of an exemplary method of forming an exemplary optical metasurface film is shown.

[0024] Figures 4 to 14 is an image of an example. DETAILED DESCRIPTION

[0025] Optical metasurface polymer films are described. These optical metasurface polymer films can be formed on flexible substrates. The flexible substrate can be a large format substrate, for example, with a lateral dimension greater than 300 mm. These optical metasurface polymer films can be formed using a roll-to-roll process with high fidelity.

[0026] The term "metasurface" refers to a two-dimensional subwavelength spacing or array of photonic resonators or truncated waveguides that perform one or more optical functions. Each array locally acts on one or more physical properties of light (specifically, amplitude, phase or polarization).

[0027] The shapes of representative nano-features of photonic resonators or truncated waveguides include, but are not limited to, rectangular, triangular, and trapezoidal prisms; fins, cylindrical, and truncated conical pillars, etc. The features can be placed in regular or random spacing, orientation, and shape, depending on the application functionality and the determined article design.

[0028] The term "nanostructure" refers to features having at least one dimension that is less than 1 micron.

[0029] The term "aspect ratio" refers to the ratio of feature height to feature width.

[0030] The term "refractive index" refers to the absolute refractive index of a material, which is understood to be the ratio of the speed of electromagnetic radiation in free space to the speed of the radiation in the material, where the radiation is green light having a wavelength of about 532 nanometers (nm). The refractive index can be measured using known methods and is typically measured using an Abbe refractometer.

[0031] The term "flexible polymer film" refers to a polymer film that can be elastically bent to a radius of curvature of 52 mm or less.

[0032] The term "manipulated phase distribution" refers to the phase distribution imposed by a metasurface on incident electromagnetic radiation. It is designed to perform a specific optical function.

[0033] The phrase "land region thickness" refers to the height of the structured surface layer between its bottom surface and the plane defined by the bottoms of the surface features. Also referred to as the residual layer or region.

[0034] The term "precision substrate" refers to a structured surface layer with a defined, controlled substrate thickness. Two examples are a minimized substrate that is capable of subsequent etching steps and a substrate that will define feature heights in the final film. Ideally, when the structured surface is capable of subsequent etching steps, the residual layer thickness will be less than the feature height. When the substrate thickness defines the height of the features in the final film, the variability in substrate layer thickness is ideally less than 25% of the layer thickness, more preferably less than 10%, and most preferably less than 5%.

[0035] The term "uncontrolled matrix" refers to a structured surface layer with an arbitrary matrix thickness. The layer thickness variability can be greater than 25%.

[0036] The supersurface polymer film can be formed by any available nanoreplication technology. Nanoreplication refers to a continuous thermal or photochemical process that uses a cylindrical tool and a polymer support film roll with a thermoplastic (thermal) or UV curable resin (photochemical) layer to produce a nanostructured surface layer. An exemplary nanoreplication technology is nanoimprint lithography (NIL).

[0037] Nanoimprint lithography (NIL) is a high-throughput technology for patterning polymer nanostructures with high precision and low cost. Unlike conventional photolithography methods that achieve pattern definition through photon or electron beam exposure of a photoresist layer to change the chemical and physical properties of the photoresist, NIL relies on the use of a stamp in direct mechanical deformation of the photoresist material. The stamp is made from a master wafer and can be reused in a rapid process to produce many copies of the original pattern.

[0038] Optical applications for direct-view electronic displays, especially display light control films for high-resolution, full-color displays, take advantage of substrate transparency, low latency, high optical efficiency, and low cost per unit area, for example. The limited size of standard wafer substrates (often used with NILs) and their high unit cost make them generally unsuitable for use as light enhancement elements, diffusers, polarizers in direct-view consumer displays. Wafer-scale optics are generally relegated to size-limited micro-optical elements such as microlens arrays, diffraction gratings, and waveguide optics.

[0039] Although large-size (greater than 1m×1m) display glass panels are used to manufacture display backplanes, patterning techniques and equipment (usually photolithography steppers) have limited resolution and cannot be used to produce nanostructure features. The use of polymer film substrates with designed nanostructured surfaces allows the size of nano-patterned components to exceed the size of semiconductor wafers, and in practice, their diameter is limited to 300mm or less. Nano-patterned polymer films can have dimensions of 1m wide×1km long or indefinite lengths. Polymer films can provide transparency across the visible and NIR spectra required for many applications.

[0040] Optical metasurface polymer films utilize the design of subwavelength structures or features that impose abrupt phase shifts at the interface of the subwavelength structures and the surrounding medium. The arrangement of these subwavelength structures or features on the polymer film provides an operational phase distribution of the optical metasurface film. Therefore, the predetermined operational phase distribution of the optical metasurface film can be modeled to determine the arrangement of these subwavelength structures or features on the polymer film.

[0041] Optical metasurface polymer films are described. These optical metasurface polymer films can be formed on flexible substrates. The flexible substrate can be a large format substrate, for example, with a lateral dimension greater than 300 mm, or greater than about 400 mm, or greater than about 500 mm. The flexible substrate can form a web of indefinite length. These optical metasurface polymer films can be formed using a roll-to-roll process with high fidelity.

[0042] Metasurfaces can exploit the design of subwavelength structures that can impose abrupt phase shifts at interfaces. In particular, along a path (x → ) obtains the generalized Snell's refraction law:

[0043] n r sin(θ t )-n i sin(θ i )=(λ0 / 2π)(dΦ / dx)

[0044] Among them, n i and n tare the refractive indices experienced by the incident and transmitted light, θ i and θ t are the angles of incidence and refraction, and λ0 is the wavelength of incidence in vacuum. Thus, achieving this phase discontinuity at the interface allows for anomalous refraction.

[0045] Although there are many ways to design elements that can impose phase discontinuities on functional metasurfaces, the Pancharatnam-Berry phase (or geometric phase) method is utilized here as an example for designing metasurfaces. This allows us to use a single element with different orientation angles, which greatly reduces the number of optimization parameters. In addition, since the resulting phase depends only on the rotation angle of the basic nanostructure, this method is very robust to manufacturing errors, as the rotation angle is usually a well-controlled parameter in manufacturing compared to the structure size.

[0046] In order to realize the Pancharatnam-Berry phase metasurface, rectangular T with different width (W), length (L) and height (H) are i O2 nanofins are modeled. Typically, H is constant across the metasurface as this facilitates fabrication. However, this is not a requirement.

[0047] When light propagates through the nanofin in the +z direction, it experiences different effective refractive indices along the W and L directions, respectively. For certain W and L dimensions, the nanofin acts as a half-wave plate (HWP), i.e., linearly polarized light propagating along one principal axis will experience a π phase shift relative to linearly polarized light propagating along the other principal axis.

[0048] Thus, the nanofin converts right circularly polarized (RCP) light (which can be decomposed into two orthogonal linear polarization states with a relative +π / 2 phase difference) into left circularly polarized (LCP) light (which can be decomposed into two orthogonal linear polarization states with a relative -π / 2 phase difference), and vice versa. If the nanofin dimensions deviate from the ideal parameters that make it a half-wave plate, then circularly polarized light will only be partially converted to its opposite handedness.

[0049] To realize this metasurface, T i A parametric sweep of O2 nanofin dimensions to find structural dimensions for an effective HWP. The sweep can be performed for different dielectric environments where the nanofins are surrounded by air or various embedding polymers or materials. In addition to nanofins with vertical sidewalls, nanofins with different sidewall draft angles (taper angles) can be utilized to reflect the manufacturing constraints dictated by the direct replication manufacturing method.

[0050] Lumerical's commercially available finite-difference time-domain (FDTD) solver can be used to simulate and analyze the properties of the nanofins and determine the optimal nanofin geometry that satisfies the manufacturing constraints and acts as a HWP. The FDTD solver provides a time-step solution to Maxwell's equations with boundary conditions specified by the user. After Fourier transformation of the time domain solution, the results can be analyzed in the frequency domain.

[0051] The measurements can be made at a wavelength of 532 nm, which is roughly in the center of the visible spectrum and facilitates subsequent measurements using widely available green lasers.

[0052] The size of the simulation grid (the spacing between discrete locations where Maxwell's equations are solved for each time step) can be set to 10 nm in the x, y, and z dimensions to minimize stair-casing effects introduced by the Cartesian grid used in the FDTD method. The simulation setup can demonstrate the Pancharatnam-Berry phase T operating in the visible spectrum. i O2 nanofin metasurface.

[0053] In order to find the optimal nanofin size in different embedded materials, a parameter scan for different nanofin sizes and sidewall taper angles can be performed. Assume that the nanofin is embedded in an optical resin. The incident light can be set to come from the substrate side, with RCP polarization, and propagate toward the nanofin. The electric field and magnetic field data of the transmitted light can be collected near a position at a wavelength distance from the top of the nanofin. Then, the far-field transformation produces the amplitude and polarization information of the transmitted light. By comparing the relative phase and amplitude of the x and y polarized light of the transmitted light in the far field with a reference geometry containing only a quartz substrate without nanofins, the RCP to LCP conversion efficiency of each nanofin and its transmission amplitude can be measured. For each combination of embedded material and sidewall taper angle, the nanofin size that most closely produces HWP behavior and therefore produces the highest conversion efficiency of circularly polarized light can be determined.

[0054] Figure 1 is a schematic cross-sectional view of an exemplary optical metasurface film 100 . Figure 2 Four representative optical metasurface films are shown in top elevation view. The optical metasurface film may include Figure 2 One or more aspects of a representative optical metasurface film shown in . Figure 2 The optical metasurface films shown in are non-limiting illustrative nanostructure morphologies.

[0055] The optical metasurface film 100 includes a flexible polymer film 101 having a first major surface, a patterned polymer layer 103, and a refractive index contrast layer 104, wherein the patterned polymer layer 103 has a first surface adjacent to the first major surface of the flexible polymer film 101 and has a second nanostructure surface opposite to the first surface, and the refractive index contrast layer 104 includes a refractive index contrast material adjacent to the nanostructure surface of the patterned polymer layer 103, thereby forming a nanostructure bilayer 105 having a nanostructure interface 106. The nanostructure bilayer 105 locally acts on the amplitude, phase or polarization of light or a combination thereof, and applies an optical phase shift that varies with the position of the nanostructure bilayer 105 on the flexible polymer film 101. The optical phase shift of the nanostructure bilayer 105 defines a predetermined operating phase distribution of the optical metasurface film 100.

[0056] The nanostructured bilayer may further include an etch stop layer 102 separating the patterned polymer layer 103 from the first major surface of the flexible polymer film 101. The etch stop layer may be an etch-resistant layer that is used to define a common etch depth during a wet or dry etching process. The etch stop layer 102 may have a thickness greater than 2 nm and up to about 25 nm. The etch stop layer may be formed of metals and their oxides and nitrides, including oxides or nitrides of Si, Al, Ti, Zr, Ta, Hf, Nb, Ce, and mixtures thereof.

[0057] The nanostructured double layer can locally act on the amplitude of light. The nanostructured double layer can locally act on the phase of light. The nanostructured double layer can locally act on the polarization of light. The nanostructured double layer can locally act on the amplitude of light and the phase of light. The nanostructured double layer can locally act on the amplitude of light and the polarization of light. The nanostructured double layer can locally act on the phase of light and the polarization of light.

[0058] The flexible polymer film can be formed of a thermoplastic material. The flexible polymer film can be formed of polyester, copolyester, polycarbonate, polyurethane, poly(methyl methacrylate), polystyrene, polyimide, polyethylene naphthalate, polypropylene, polycycloolefin, preferably polyester and polycarbonate. The flexible polymer film can have a uniform thickness. The average thickness of the flexible polymer film can be in the range of about 5 microns to about 300 microns. The flexible polymer film can have a uniform thickness in the range of 10 microns to 250 microns or 25 microns to 125 microns. The flexible film can exhibit optical delay.

[0059] The nanostructured bilayer may be defined by a solid material. The nanostructured bilayer may be formed of a solid material. The nanostructured bilayer may be formed of a polymeric material.

[0060] The patterned polymer layer can be formed of a thermoplastic material. The patterned polymer layer can be formed of poly(methyl methacrylate), polycarbonate, polypropylene, polyethylene, polystyrene, polyester, polyamide. The patterned polymer layer can be formed of a polymerizable composition comprising an acrylate or methacrylate component. The patterned polymer layer can include a fluoropolymer, a (meth)acrylate (co)polymer, or a silicon dioxide-containing polymer.

[0061] The index contrast material may have a first refractive index value and the patterned polymer layer has a second refractive index value that differs from the first refractive index value by at least 0.25, or by 0.5, or by 0.75, or by 1.0, or by 1.4.

[0062] The refractive index contrast material may have a first refractive index value in the range of 1.7 to 2.5. The patterned polymer layer has a second refractive index value in the range of 1.2 to 1.6.

[0063] The refractive index contrast material may include a metal oxide or a metal nitride. The refractive index contrast material may include at least one of titanium, zirconium, tantalum, hafnium, niobium, zinc, or cerium; an oxide of titanium, zirconium, tantalum, hafnium, niobium, zinc, or cerium; a nitride of titanium, zirconium, tantalum, hafnium, niobium, zinc, or cerium; a sulfide of titanium, zirconium, tantalum, hafnium, niobium, zinc, or cerium; or a combination thereof.

[0064] The patterned polymer layer may include a fluorinated acrylate and the refractive index contrast material may include titanium dioxide.The patterned polymer layer may include a (meth)acrylate and the refractive index contrast material may include titanium dioxide.

[0065] The nanostructure bilayer may be defined by a plurality of nanostructures embedded in the refractive index contrast layer. The aspect ratio of the nanostructures forming the nanostructure surface may be at least about 1:1, 2:1, 5:1, 10:1, or 15:1. The aspect ratio of the nanostructures forming the nanostructure surface is preferably in the range of about 2:1 to about 20:1, or about 4:1 to about 15:1.

[0066] The nanostructures forming the nanostructure surface may define a tapered sidewall having an angle in the range of about 1 to 10 degrees, 2 to 10 degrees, 3 to 10 degrees, 4 to 10 degrees, 1 to 6 degrees, 2 to 6 degrees, or 3 to 6 degrees, or 2 to 4 degrees. The nanostructures forming the nanostructure surface may define a tapered sidewall having an angle in the range of about 0 to 10 degrees, 0 to 6 degrees, 0 to 3 degrees, 0 to 2 degrees, 0 to 1 degree, or 0 degrees.

[0067] The height of the nanostructures forming the nanostructured surface may be 5 micrometers or less, or in the range of about 100 nanometers to about 3000 nanometers, or about 500 nanometers to about 1500 nanometers.

[0068] The nanostructures forming the nanostructured surface have an average spacing (center-to-center distance between adjacent nanostructures) that is sub-wavelength relative to the shortest wavelength contained in the interrogating electromagnetic radiation.

[0069] For an optical metasurface operating in the visible spectrum, the average spacing of the nanostructures forming the nanostructure surface may be 600 nanometers or less, or 500 nanometers or less, or 400 nanometers or less. For an optical metasurface operating in the visible spectrum, the average spacing of the nanostructures forming the nanostructure surface may preferably be 50 nanometers to 600 nanometers, or 100 nanometers to 500 nanometers, or 200 nanometers to 400 nanometers.

[0070] The nanostructures forming the nanostructured surface are spaced apart from each other at a sub-wavelength lateral distance. The nanostructures forming the nanostructured surface are spaced apart from each other by about 400 nanometers or less, or in the range of about 20 nanometers to about 400 nanometers, or about 50 nanometers to about 300 nanometers.

[0071] The nanostructures forming the nanostructured surface have a lateral dimension orthogonal to the nanostructured feature height, which is sub-wavelength. The nanostructures forming the nanostructured surface may have a lateral dimension orthogonal to the nanostructured feature height, which is about 600 nanometers or less or in the range of about 10 nanometers to about 400 nanometers, or in the range of about 50 nanometers to about 350 nanometers.

[0072] Optical phase shift can occur in the visible wavelength range. Optical phase shift can occur in the near IR wavelength range. Optical metasurface films can transmit visible light or near infrared light.

[0073] The nanostructures forming the nanostructure surface may have different orientations, depending on the position of each nanostructure on the flexible polymer film. The nanostructures forming the nanostructure surface may have different spatial arrangements, depending on the position of each nanostructure on the flexible polymer film. The nanostructures forming the nanostructure surface may have different shapes, depending on the position of each nanostructure on the flexible polymer film. The nanostructures forming the nanostructure surface may have different aspect ratios, depending on the position of each nanostructure on the flexible polymer film.

[0074] The nanostructures forming the nanostructure surface may be geometrically anisotropic in the planar direction. The nanostructures forming the nanostructure surface may be geometrically isotropic in the planar direction.

[0075] Figure 3 A cross-sectional schematic diagram of an exemplary method of forming an exemplary optical metasurface film is shown.

[0076] The manufacturing method utilizes a hard mask layer that also serves as a second etch stop layer. Including a hard mask layer has four beneficial effects. First, since the etching of a thin hard mask layer does not require high aspect ratio photoresist features, it reduces or eliminates the need for a near-zero substrate photoresist replication process. Second, the photoresist material for nano-replication can be an acrylate resin formulation rather than a silicon-rich hybrid material. Third, the hard mask etching process enables the formation of deep vias with vertical sidewalls (important for optical metasurface applications). Finally, since the vapor deposition step for the hard mask layer forms an inorganic layer with good adhesion and good wettability to the nano-replication resin layer, the construction allows the use of a low refractive index pattern transfer layer (e.g., fluorinated acrylate).

[0077] It utilizes an input roll for a nano-replication process, which includes a polymer support film, and an etch stop layer, a precision pattern transfer layer, and a hard mask layer. A process such as roll-to-roll nanoimprint lithography (R2R NIL) is required to form a near-zero etch resist layer of the substrate structure in the first process step, but substrate control can be relaxed. Since the structure is etched through the entire pattern transfer layer thickness, the layer thickness ultimately defines the feature height in the final article. This process is useful if both feature height uniformity and absolute feature height of surface features in the final article are critical (e.g., for optical metasurface applications), and the embedded optical element has a low refractive index organic layer and a higher refractive index metal oxide backfill layer.

[0078] The material used for the pattern transfer layer can be used as a low refractive index material or a high refractive index material in the embedded optical element.

[0079] The film including the polymer support film, etch stop layer, precise pattern transfer layer and hard mask layer 410 is used as an input roll for R2RNIL or continuous casting and curing (Process 4A, “R2RNIL”). The nanoreplication film 420 is etched in a reactive ion etching (RIE) process until the top surface of the hard mask layer has been exposed (Process 4B, “breakthrough etch”) to produce an intermediate 430. After this step, some resin residue may remain and can be removed in an optional additional RIE step (Process 4C). The hard mask patterned intermediate 440 is further etched using a second etching chemistry in a second RIE process until the pattern transfer layer is etched to the etch stop layer (Process 4D). The etched nanopatterned film with hard mask residue 450 can be planarized with a high refractive index backfill to form an embedded nanopatterned optical film 460 (Process 4E), or subjected to different etching conditions to remove the hard mask residue to form an unfilled nanopatterned optical film 470 (Process 4F). Finally, the unfilled nano-patterned optical film 470 may be planarized with a high refractive index backfill material to form an embedded nano-patterned optical film 370 .

[0080] Example

[0081] Material

[0082]

[0083]

[0084]

[0085]

[0086] All concentrations are in weight percent

[0087] Example 1: Functional blazed grating with low residue transfer on PETg prepared by four-layer method

[0088]

[0089]

[0090] All concentrations are in weight percent

[0091] Step a: Replication of nanofeatured template films

[0092] Compound 01 containing 0.5% AEBP was added to the mold via a peristaltic pump and onto a 5 mil polycarbonate film. The resin coated film was pressed against a circular nickel sleeve controlled at 140 degrees Fahrenheit, which had a nanoscale pattern welded into it. The sides of the features ranged from 100nm to 350nm and were 200nm high. Nominal zero vertical drawing. While in contact with the nickel sleeve, the resin coated film was exposed to radiation from two Fusion lamps operating at 142W / cm. The nanostructured film was then peeled off from the circular nickel sleeve. The process was run continuously for over 1000 feet at 25fpm. Figure 4 is a 50kX top view of replicated features on a nanoreplicated photoresist transfer film and shows the sample area.

[0093] Step b: Release treatment of nano-feature templated membrane

[0094] The processed film of step (a) was subjected to release treatment using PECVD. First, the film was pretreated by flowing O2 into the chamber at 500 cfpm and 30 fpm at 2000 W plasma power.

[0095] The membrane was then treated with HMDSO at 1000 watts at 30 fpm. Figure 5 is a 50kX perspective view of the replicated features after release processing.

[0096] Step c: Applying acrylate to the template film

[0097] The processed film (b) after release treatment was die coated with a solution of 13% Compound 03, 1% Compound 05, 43% MEK and 43% Dowanol PM at 10 fpm. The coating was pre-cured with a 0.2 amp UV-LED system during a coating time of 30 seconds. A very thin residual layer is desired so that the residual layer thickness can be controlled between zero and 500 nm with fixture precision using a predetermined coating method. This coating method uses a solution of at least 50% solvent.

[0098] Step d: Drying the Acrylate on the Processing Film

[0099] The solvent was allowed to evaporate from the membrane (C) over a free span of 40 ft. To prevent disturbing the wet membrane, no heat or convection was used to dry the solvent.

[0100] Step e: Three-layer film formation (to be laminated to the acrylate-coated template film)

[0101] Since this film is part of the final structure, a PET-g film was selected because of its low in-plane retardation as specified by the optical design. The PET-g film is described in the filed WO2019032635A1. Figure 2middle. Figure 2 is a side view of a four-layer film with an ADBC ​​layer construction. The film includes the following layers in the construction, as shown: orientation layer A; tie layer D; peel layer B; and isotropic layer C. Wherein orientation layer A is polyester (PET); tie layer D is a linear triblock copolymer based on styrene and ethylene / butylene (G1645 from Kraton); peel layer B is a mixture of polypropylene (PP9074MED from ExxonMobil International) and a linear triblock copolymer based on styrene and ethylene / butylene (G1645 from Kraton); isotropic layer C is PETg (Eastar GN071 from Eastman). This film construction provides additional ability to control where the first separation of the layers occurs (in this case between layers B and C).

[0102] SiAlOx was deposited from a 90% Si / 10% Al target by dual cathode AC reactive sputtering at 1.5 mTorr and 16 kW plasma power in an O2 / Ar atmosphere. The coating speed was 16 fpm to obtain a 25 nm thick coating. Acrylate was deposited by a vapor deposition method as disclosed in patent US9302291. A mixture of 88% SR833, 4% compound 02, 4% Dynasilan 1189 and 4% Irgacure184 was added to the evaporator as a photoinitiator, and a steady stream of vapor was passed through the coating die to a cooled substrate moving at 24 fpm, where the mixture condensed and immediately cured by UV or low-voltage electron beam. Compound 02 and Dynasilan were used to promote adhesion between SiAlOx and acrylate. The final thickness of the acrylate layer was 1100 nm. Another 25 nm SiAlOx layer was deposited on top of the acrylate layer in the same manner as the first layer.

[0103] Step f: Adhesion promoter on top of SiAlOx (to promote adhesion of the tri-layer interlayer to low substrate patterned acrylate)

[0104] Compound 02 was die coated at 20 fpm with MEK on SiAlOx at 7.5 nm. The solvent was evaporated and the film was annealed for 1.5 minutes at 200° F. Compound 02 was then cured using a Fusion E bulb.

[0105] Step g: Lamination

[0106] The coated processed film was laminated to the SiAlOx + Compound 02 film using a 90 durometer nip and a water heated roller set at 170F at 10 fpm. The film was then cured using a 600W Fusion H bulb.

[0107] Step h: Peeling

[0108] Shortly after the water heated rollers, the structured acrylate was peeled from the structured HMDSO film to the SiAlOx film (minimizing web twisting to reduce strain). All films were tensioned at about 1 pli, still running at 10 fpm. Figure 6 50kX perspective view of SiAlOx / acrylate / structured acrylate on SiAlOx peeled onto PETG (low substrate film). Figure 7 This is a 50kX cross-sectional view image before etching or punch-through. Note the very low residual layer thickness exposing the top mask layer in the via.

[0109] Steps i and j: Etching the residual layer and penetrating the SiAlOx mask

[0110] These steps can be performed separately, such as oxygen etching followed by fluorine etching, or subsequently during a single fluorine etching. The latter path is chosen here. In this case, the reactive ion etching is performed with 100 sccm of NF3, running at 7500 watts, 12.5 ft / min, and a pressure of 3 mTorr.

[0111] Step k: Through Etching

[0112] A second reactive ion etch was performed with 700 sccm of O2 at a base pressure of 0.3 mTorr, 7500 Watts, a speed of 15 ft / min, and a pressure of 5.2 mTorr to remove the transferred layer in the portions where the mask had been removed. Figure 8 is a 50kX top view of the nanolithographically patterned membrane after through etching. Fig. 9 is a 50kX cross-sectional view image of the sample after O2 etching.

[0113] Step 1: High refractive index backfill

[0114] Etched high aspect ratio features were processed in a spatial rotation ALD machine. Titanium tetraisopropoxide (TTIP) heated to 65°C (passive transfer) and a DC plasma discharge (350 mA) in an environment of 1 Torr of N2 and 0.3 Torr of O2 was used to deposit T. i O2. The chamber and substrate were heated to 80°C. The substrate was fixed in a drum rotating at 30 RPM, with one precursor and plasma exposure occurring once per revolution for a total of 4688 ALD cycles, resulting in a 217 nm thick T i The refractive index of the O2 layer measured at a wavelength of 632 nm is 2.33. Fig.10 It is T i 50Kx cross-sectional SEM view of the O2 backfilled sample. In this image, the brighter areas are T i O2, and the darker areas are acrylate resins.

[0115] Optical image analysis ( Fig.11 and Fig.12 )

[0116] The blazed grating was analyzed using a laser, where the sample was placed between two orthogonal linear polarizers. The blazed grating optical metamaterial sample on PET film 1 (DuPont ST504) showed multiple peaks due to the in-plane optical retardation \Δn = 0.048. The stray spots were eliminated on the low optical retardation PETg sample ( Fig.12 ).Notice, Fig.12 The “fuzzy” spots observed in are due to thermal degradation of PETg during ALD coating at 100 C.

[0117] Example 2: Using a low refractive index compound as a transfer layer

[0118] The purpose of low refractive index materials is to increase T i The refractive index change between O2 and the embedded resin improves the optical performance. In step E, a three-layer film is formed: using a fluorinated low-refractive index material, compound 04 replaces 1100nm acrylate. PET film 2 is used instead of PETg, although this should not be important for processing purposes. A 25nm SiAlOx base etch stop layer is sputtered onto a PET (ST505) film. The etch stop layer is then vapor-coated with a layer of 96% compound 02 and 4% Darocur 1173, with a thickness of about 15nm. Maintain a line speed of 65fpm while keeping the back of the film in contact with a coating drum cooled to 0°C. With the back in contact with the drum, the SiAlOx surface is treated with a dc nitrogen plasma at a nitrogen pressure of 100W and 150mTorr. Immediately after the nitrogen plasma treatment, the SiAlOx surface is coated with compound 02 / Darocur 1173 using the organic vapor deposition system and method described in U.S. Patent No. 8,658,248. Before coating, the monomer was degassed under vacuum to a pressure of 20 mTorr. The liquid was pumped into an ultrasonic atomizer at a liquid flow rate of 0.1 ml / min using a syringe pump, and a nitrogen flow rate of 10 sccm was input into the atomizer. The liquid was flash evaporated at 250°C and delivered to the SiAlOx surface. The vapor stream was condensed onto the film surface and cured by UV radiation using a low-pressure mercury arc lamp.

[0119] While maintaining vacuum, the Compound 02 / Darocur 1173 layer was vapor coated with an acrylate layer of 97.5% Compound 04 and 2.5% Darocur 1173 to a thickness of about 1100 nm. A line speed of 12.5 fpm was maintained while the back of the film was kept in contact with a coating drum cooled to 0°C. With the back in contact with the drum, the Compound 02 surface was coated with the Compound 04 / Darocur 1173 mixture using an organic vapor deposition system and method described in U.S. Patent No. 8,658,248. Prior to coating, the monomer was degassed under vacuum to a pressure of 20 mTorr. A syringe pump was used to pump the liquid into an ultrasonic atomizer at a liquid flow rate of 2.05 ml / min, and a nitrogen flow rate of 10 sccm was input into the atomizer. The liquid was flashed at 250°C and delivered to the Compound 02 surface. The vapor flow was condensed onto the film surface and cured by UV radiation using a low-pressure mercury arc lamp.

[0120] A 25 nm thick SiAlOx top etch stop layer was deposited onto the Compound 04 / SiAlOx coated film as described in "Methods for Vapor Coating of Etch Stop and Transfer Layers".

[0121] Etching through any substrate and SiAlOx mask in one step: Reactive ion etching with 100 sccm of C6F14 at 0.5 mTorr base pressure, 7500 Watts, 4 ft / min rate, 6.3 mTorr pressure and 0.5 mTorr base pressure. Breakthrough etch: A second reactive ion etch with 275 sccm of O2 at 0.4 mTorr base pressure, 7500 W, 6 ft / min rate, 4.7 mTorr pressure removes the transferred layer in the portion where the mask has been removed. Fig.13 are cross-sectional and perspective images of an array of features etched in the Compound 04 layer. Fig.14 is a close-up cross-sectional view image of a via etched in the Compound 04 layer.

[0122] Example 3 - Results

[0123] The effect of embedding nanofins in a replica resin with refractive index data is studied. First, the effect of the embedding medium on the optical properties of nanofins with vertical sidewalls is studied. i The refractive index contrast between the O2 nanofin and the surrounding dielectric environment is reduced, and the effective refractive index along the major axis of the nanofin (which can be considered as a truncated dielectric waveguide) is reduced. Therefore, the ideal nanofin height determined for the free-standing nanostructure no longer results in half-wave plate behavior. Light polarized along the fast axis after passing through the nanofin With light polarized along the slow axis The phase difference between Given by:

[0124]

[0125] Among them, Δn eff is the effective refractive index difference between the fast axis and the slow axis, and H is the height of the nanofin. For the nanofin in air and the nanofin embedded in photoresist, the difference in effective refractive index is Δn eff，air ≈0.44 and Δn eff，embedded ≈0.2. To restore the half-wave plate behavior of the embedded nanofins, the height needs to be increased to balance the loss of effective refractive index contrast. For embedding media with n=1.35 and n=1.5, the height of the embedded nanofins may preferably be about 1100 nm and about 1500 nm, respectively.

[0126] When the appropriate nanofin height is chosen, good RCP to LCP conversion efficiency can be achieved in different embedding media. However, the higher refractive index environment supports more guided mode resonances, which leads to a sharper drop in the conversion efficiency spectrum. This effect is expected to be suppressed in practical metasurfaces where the nanofins are not perfectly aligned but rotated relative to each other.

[0127] Next, the effect of the taper angle on the performance of the embedded nanofins was studied. Increasing the sidewall taper angle can result in the height of the nanofin being cut off while limiting the maximum base size. The taper angle can be limited to 3 degrees and 2 degrees in order to maintain the preferred heights of 1100nm and 1500nm, respectively. Similar to what has been observed for tapered nanofins in air, we see that for increasing taper angles, high RCP to LCP conversion efficiencies can only be achieved for smaller bandwidths. For the embedded structure, a sidewall taper angle of 2 degrees maintains a conversion efficiency greater than 50% in the visible spectral range.

[0128] To evaluate the performance of the optimized nanofins in functional optical metasurfaces, we studied their behavior when used to construct a Pancharatnam-Berry phase gradient metasurface. Specifically, six elements were placed on a superperiod of Λ, where each nanofin was rotated 30° counterclockwise relative to its neighbor to the left. This metasurface acts as a blazed grating with an offset angle given by:

[0129] θ=arcsin(λ / Λ),

[0130] At the design wavelength λ = 532 nm and super period Λ = 1950 nm, this yields an offset angle of 15.8° from normal incidence.

[0131] Electromagnetic full-field simulations were performed on a gradient metasurface consisting of nanofins with a base size of 120nm × 300nm. The nanofins were surrounded by air and had vertical sidewalls or taper angles of 4° and 8°. The resulting diffraction efficiencies were 97%, 90%, and 63% for vertical, 4°, and 8° tapers, respectively. The decrease in efficiency with increasing sidewall taper angle is consistent with previous findings for individual nanofins.

[0132] Based on the results obtained from previous studies, optical metasurfaces were designed for exploring measurement wafers for direct nanoreplication (called H1) and nanoimprint lithography (H2) approaches.

[0133] The measurement wafer H1 includes designs H1A and H1B (Table 1), both of which consist of 600nm high nanofins embedded in an n=1.52 resin with sidewalls tapering at an angle of 4°. Due to the height restrictions imposed by the fabrication method, the individual nanofins operate approximately as quarter-wave plates. This results in reduced circular polarization conversion efficiency compared to the ideal case of half-wave plate nanofins. For H1A, a gradient metasurface with an offset angle of 4.7° was designed. H1B consists of perfectly aligned nanofins to study fabrication variations.

[0134]

[0135] Table 1: Design parameters for the measurement wafer H1 consisting of metasurfaces H1A and H1B

[0136] The measurement wafer H2 includes designs H2A, H2B and H2C (Table 2). All designs use 1100 nm high straight-walled nanofins embedded in a resin with a refractive index of n = 1.36. H2A consists of nanofins with a base size of 120 nm × 300 nm, which act as a half-wave plate. A blazed grating with an offset angle of 4.8° was designed.

[0137] H2B and H2C consist of switchable holograms (cat / dog and 3M / Harvard logos, respectively) that present different images for orthogonal states of linearly polarized light. In contrast to the periodic patterns used for H1A and H2A, H2B and H2C contain non-repeating patterns of nanofins with different basis sizes in order to generate a wide range of local phases via the propagating phase method. The images were encoded into computer-generated holograms via the Gerchberg-Saxton algorithm.

[0138]

[0139] Table 2: Design parameters for the measurement wafer H2 including metasurfaces H2A, H2B and H2C.

[0140] Tables 3A and 3B show the relative performance of nanofins with a base size close to the optimal half-wave plate nanofin in an embedded medium with a refractive index of 1.36. In order to meet the manufacturing constraints requiring a minimum feature size of 80nm, a compromise was made to nanofins with a base size of 140nm×280nm placed in a 420nm lattice. The numbers in Tables 3A and 3B represent the relative conversion efficiency percentage from RCP to LCP at 532nm, where 140nm×280nm is set to 100%. The area in the red box contains better performance parameters. However, they are unavailable due to the 80nm feature size limitation. The errors of W (short axis) ±20nm, H (long axis) ±10nm and height ±20nm are less than 15% worse than the designed structure.

[0141] Table 3A

[0142]

[0143] Table 3B

[0144]

[0145] Table 3A and Table 3B Sensitivity analysis of T embedded in an optical resin with a refractive index of 1.5 i O2 nanofins. The numbers represent the relative conversion efficiency percentage from RCP to LCP when the 140nm×280nm×600nm nanofin is set to 100%. The errors of W (minor axis) ±20nm, L (major axis) ±10nm and H (height) ±20nm are less than 15% worse than the designed structure.

Claims

1. An optical super surface film, comprising: a flexible polymer film having a first major surface; a patterned polymer layer having a first surface adjacent to the first major surface of the flexible polymer film and having a second nanostructured surface opposite the first surface; as well as a refractive index contrast layer comprising a refractive index contrast material adjacent to the nanostructured surface of the patterned polymer layer, thereby forming a nanostructured bilayer having a nanostructured interface, the nanostructured bilayer comprising a plurality of nanostructures disposed on the flexible polymer film, wherein the nanostructured bilayer locally acts on the amplitude, phase or polarization of light, or a combination thereof, and applies an optical phase shift that varies with the position of the nanostructured bilayer on the flexible polymer film, and the optical phase shift of the nanostructured bilayer defines a predetermined operational phase distribution of the optical metasurface film, Wherein, the refractive index contrast material includes metal oxide or metal nitride.

2. The optical supersurface film according to claim 1, wherein The nanostructured bilayer contributes locally to the amplitude of light.

3. The optical supersurface film according to claim 1, wherein The nanostructured bilayer locally affects the phase of light.

4. The optical supersurface film according to claim 1, wherein The nanostructured bilayer locally affects the polarization of light.

5. The optical supersurface film according to claim 1, wherein The nanostructured bilayer is defined by a solid material.

6. The optical metasurface film of claim 1, further comprising an etch stop layer separating the patterned polymer layer from the first major surface of the flexible polymer film.

7. The optical supersurface film according to claim 1, wherein The refractive index contrast material has a first refractive index value and the patterned polymer layer has a second refractive index value that differs from the first refractive index value by at least 0.

25.

8. The optical supersurface film according to claim 1, wherein The refractive index contrast material has a first refractive index value and the patterned polymer layer has a second refractive index value that differs from the first refractive index value by 0.

5.

9. The optical supersurface film according to claim 1, wherein The refractive index contrast material has a first refractive index value and the patterned polymer layer has a second refractive index value that differs from the first refractive index value by 0.

75.

10. The optical supersurface film according to claim 1, wherein: The refractive index contrast material has a first refractive index value and the patterned polymer layer has a second refractive index value that differs from the first refractive index value by 1.

0.

11. The optical supersurface film according to claim 1, wherein: The refractive index contrast material has a first refractive index value and the patterned polymer layer has a second refractive index value that differs from the first refractive index value by 1.

4.

12. The optical supersurface film according to claim 1, wherein The nanostructured bilayer is defined by a plurality of nanostructures embedded in the refractive index contrast layer.

13. The optical supersurface film according to claim 1, wherein: The patterned polymer layer includes a fluorine-containing polymer, a (meth)acrylate (co)polymer, or a silicon dioxide-containing polymer.

14. The optical supersurface film according to claim 1, wherein: The patterned polymer layer includes a fluorinated acrylate and the refractive index contrast material includes titanium dioxide.

15. The optical supersurface film according to claim 1, wherein: The patterned polymer layer comprises (meth)acrylate, and the refractive index contrast material comprises titanium dioxide.

16. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface have an aspect ratio of at least about 1:

1.

17. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface have an aspect ratio of at least about 2:

1.

18. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface have an aspect ratio of at least about 5:

1.

19. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface have an aspect ratio of at least about 10:

1.

20. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface have an aspect ratio of at least about 15:

1.

21. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface define tapered sidewalls having an angle in a range of about 1 degree to 10 degrees.

22. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface define tapered sidewalls having an angle in a range of 2 degrees to 10 degrees.

23. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface define tapered sidewalls having an angle in a range of 3 degrees to 10 degrees.

24. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface define tapered sidewalls having an angle in a range of 4 degrees to 10 degrees.

25. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface define tapered sidewalls having an angle in a range of 1 degree to 6 degrees.

26. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface define tapered sidewalls having an angle in a range of 2 degrees to 6 degrees.

27. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface define tapered sidewalls having an angle in a range of 3 degrees to 6 degrees.

28. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface define tapered sidewalls having an angle in the range of about 0 to 10 degrees.

29. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface define tapered sidewalls having an angle in the range of 0 to 6 degrees.

30. The optical supersurface film according to claim 1, wherein: The nanostructures forming the nanostructured surface define tapered sidewalls having an angle in the range of 0 to 3 degrees.

31. The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructured surface define tapered sidewalls having an angle in the range of 0 to 2 degrees.

32. The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructured surface define tapered sidewalls having an angle in the range of 0 to 1 degree.

33. The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructured surface define a tapered sidewall, the tapered sidewall having an angle of 0 degrees.

34. The optical supersurface film according to claim 1, wherein The flexible polymer film has an average thickness in a range of about 5 microns to 300 microns.

35. The optical supersurface film according to claim 1, wherein The height of the nanostructures forming the nanostructure surface is 5 micrometers or less.

36. The optical supersurface film according to claim 1, wherein The height of the nanostructures forming the nanostructure surface is in the range of about 100 nanometers to 3000 nanometers.

37. The optical supersurface film according to claim 1, wherein The height of the nanostructures forming the nanostructure surface is in the range of about 500 nanometers to 1500 nanometers.

38. The optical supersurface film according to claim 1, wherein The average pitch of the nanostructures forming the nanostructure surface is 600 nanometers or less.

39. The optical supersurface film according to claim 1, wherein The average pitch of the nanostructures forming the nanostructure surface is 500 nanometers or less.

40. The optical supersurface film according to claim 1, wherein The average pitch of the nanostructures forming the nanostructure surface is 400 nanometers or less.

41. The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructured surface are separated from each other by about 400 nanometers or less.

42. The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructured surface are separated from each other by a range of about 20 nanometers to 400 nanometers.

43. The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructured surface are separated from each other by about 50 nanometers to 300 nanometers.

44. The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructured surface have lateral dimensions normal to the nanostructured feature height that are about 600 nanometers or less.

45. The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructured surface have lateral dimensions normal to the nanostructured feature heights in the range of about 10 nanometers to 400 nanometers.

46. ​​The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructured surface have lateral dimensions normal to the nanostructured feature heights in the range of about 50 nanometers to 350 nanometers.

47. The optical supersurface film according to claim 1, wherein The optical phase shift occurs in the visible light wavelength range.

48. The optical supersurface film according to claim 1, wherein The optical phase shift occurs in the near IR wavelength range.

49. The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructured surface have different orientations depending on the position of the individual nanostructures on the flexible polymer film.

50. The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructured surface have different spatial arrangements depending on the position of the individual nanostructures on the flexible polymer film.

51. The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructured surface have different shapes depending on the position of each nanostructure on the flexible polymer film.

52. The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructured surface have different aspect ratios depending on the location of the individual nanostructures on the flexible polymer film.

53. The optical supersurface film according to claim 1, wherein The optical supersurface film transmits visible light or near-infrared light.

54. The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructure surface are geometrically anisotropic in a planar direction.

55. The optical supersurface film according to claim 1, wherein The nanostructures forming the nanostructure surface are geometrically isotropic in the planar direction.

56. The optical supersurface film according to claim 1, wherein At least one lateral dimension of the optical metasurface film is greater than about 300 mm.

57. The optical supersurface film according to claim 1, wherein At least one lateral dimension of the optical metasurface film is greater than about 400 mm.

58. The optical supersurface film according to claim 1, wherein At least one lateral dimension of the optical metasurface film is greater than about 500 mm.

59. An optical super surface film, comprising: a flexible polymer film having a first major surface; a patterned polymer layer having a first surface adjacent to the first major surface of the flexible polymer film and having a second nanostructured surface opposite the first surface; as well as a refractive index contrast layer comprising a refractive index contrast material adjacent to the nanostructured surface of the patterned polymer layer, thereby forming a nanostructured bilayer having a nanostructured interface, the nanostructured bilayer comprising a plurality of nanostructures disposed on the flexible polymer film, wherein the nanostructured bilayer locally acts on the amplitude, phase or polarization of light, or a combination thereof, and applies an optical phase shift that varies with the position of the nanostructured bilayer on the flexible polymer film, and the optical phase shift of the nanostructured bilayer defines a predetermined operational phase distribution of the optical metasurface film, The refractive index contrast material comprises: (1) at least one of titanium, zirconium, tantalum, hafnium, niobium, zinc or cerium; (2) an oxide of titanium, zirconium, tantalum, hafnium, niobium, zinc or cerium; (3) a nitride of titanium, zirconium, tantalum, hafnium, niobium, zinc or cerium; (4) a sulfide of titanium, zirconium, tantalum, hafnium, niobium, zinc or cerium; or a combination of (1), (2), (3) and (4).

Images