Provided an imaging apparatus including a first optical device, a second optical device disposed such that light transmitted through the first optical device is incident on the second optical device, and a third optical device disposed such that light transmitted through the second optical device is incident on the third optical device, wherein at least one of the first optical device, the second optical device, and the third optical device includes a plurality of nanostructures, and heights of at least two nanostructures of the plurality of nanostructures are different from each other.

In example embodiments, a diffractive element is provided. The diffractive element may include a substrate. A plurality of grating elements are provided on the substrate. Each grating element includes a first ridge region comprising a first ridge body region and a first core element, a second ridge region comprising a second ridge body region and a second core element, and a saddle region extending between the first and second ridge regions. In some embodiments, the first ridge body, the second ridge body, and the saddle region have a first refractive index (n2), and the first core element and second core element have a second refractive index (n4) greater than the first refractive index.

A light emitting device, a method of fabricating a light emitting device and a method of controlling light emission. The light emitting device includes a plasmonic structure. The plasmonic structure is configured to have a plurality of localized surface plasmon resonances. The light emitting device also includes a broadband light emitting layer having an emission spectrum substantially overlapping wavelengths of the localized surface plasmon resonances. A spacer layer is disposed between the plasmonic structure and the broadband light emitting layer. A color of light emitted by the broadband light emitting layer is tunable by the localized surface plasmon resonances of the plasmonic structure.

A multi-view pixel directional backlight module and a naked-eye 3D display device are provided. The multi-view pixel directional backlight module includes at least two rectangular light guide plates closely stacked together. A light-emerging surface of the rectangular light guide plate is provided with multiple pixel arrays. Light emitted by pixels in a same pixel array is pointed to a same viewing angle, and different pixel arrays have different viewing angles. At least one side of each rectangular light guide plate is provided with a light source group. Light emitted by the light source group enters the corresponding light guide plate, then emerges from pixels of respective pixel arrays on the light-emerging surface of the light guide plate, and is totally reflected at positions other than positions of the pixels within the light guide plate. Each of the pixels is a nano-diffraction grating.

A method forms a pattern of metallic nanofeatures that generates by plasmonic resonance a desired image having a distribution of colors. The method includes providing a substrate having a layer of photosensitive material, exposing the layer to a high-resolution periodic pattern of dose distribution, and determining a low-resolution pattern of dose distribution such that the sum of the low-resolution pattern and the high-resolution periodic pattern of dose distribution is suitable for forming the pattern of metallic nanofeatures. The lateral dimensions of the metallic nano-features have a spatial variation across the pattern that corresponds to the distribution of colors in the desired image. The layer of photosensitive material is exposed to the low-resolution pattern of dose distribution. The layer of photosensitive material is developed to produce a pattern of nanostructures in the developed photosensitive material. The pattern of nanostructures is processed so that the pattern of metallic nanofeatures is formed.

A grating device includes a supporting body having a first main face and a second main face, an under clad layer provided on the first main face of the supporting body, an optical material layer provided on the under clad layer, and a back face layer provided on the second main face of the supporting body. The under clad layer is composed of g a material having a refractive index of 1.69 or lower. The optical material layer is composed of a metal oxide having a refractive index of 1.70 or higher and 3.50 or lower and includes a Bragg grating. The back face layer is composed of a material having a refractive index of 1.69 or lower or a metal oxide having a refractive index of 1.70 or higher and 3.50 or lower.

Manufacturing an optical device includes providing a substrate (102) having a polymeric layer (104) on a surface of the substrate, forming openings in the polymeric layer, and depositing a material in the openings to form meta-atoms (114, 214) of a first metastructure. Adjacent ones of the meta-atoms are separated from one another by polymeric material of the polymeric layer. Optical devices that include one or more metastructures in which meta-atoms are separated from one another by polymeric material are described, as are modules that incorporate the optical devices.

There is disclosed a protected item including an item that needs protection and a protective coating having a hardness of at least about 8 on the Mohs scale. The protected item includes a light transmission in part or all of the visible wavelength of at least about 60% and a light reflection in the visible wavelength of about 4% or less.

A metalens, a metalens set, and a method of image construction or decryption are disclosed. The metalens includes metastructures each having a shape and a height related to a resonant light wavelength of the metastructure, so that the metalens can present an incident light of the resonant light wavelength as a light shape or light pattern at a far-field position matching the resonant light wavelength. A metalens set formed by staking the metalenses vertically can present incident lights having different resonant wavelengths as light shapes, light patterns, or resolved images at far-field positions matching the resonant wavelengths. Image construction or decryption are achieved by combining resolved images of the resonant light wavelengths with non-resolved images of non-resonant light wavelengths so as to compose an overlay image, which is to be decomposed by the metalens or the metalens set so as to recover the resolved images.

Electromagnetic wave focusing devices and optical apparatuses including the same are provided. An electromagnetic wave focusing device may include a plurality of material members located at different distances from a reference point. The intervals and/or widths of the material members may vary with distance from the reference point. For example, the intervals and/or widths of the material members may increase or decrease with distance from the reference point. The intervals and/or widths of the material members may be controlled to satisfy a spatial coherence condition with the electromagnetic wave.