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US-20260126634-A1 - OPTICAL ELEMENT AND METHOD OF MANUFACTURING OPTICAL ELEMENT

US20260126634A1US 20260126634 A1US20260126634 A1US 20260126634A1US-20260126634-A1

Abstract

Provided is an optical element including: a substrate; and a metasurface formed on the substrate, the metasurface including a first metaatom through which light is capable of propagating, and a second metaatom through which light is capable of propagating, wherein the second metaatom differs from the first metaatom in refractive index, the first metaatom having the same material composition as a material composition of the substrate.

Inventors

  • Junzo Kobayashi
  • Kentaro Mori
  • KANAKO SHIMBA

Assignees

  • CANON KABUSHIKI KAISHA

Dates

Publication Date
20260507
Application Date
20251029
Priority Date
20241107

Claims (20)

  1. 1 . An optical element comprising: a substrate; and a metasurface formed on the substrate, wherein the metasurface includes a first metaatom through which light is capable of propagating, and a second metaatom through which light is capable of propagating, wherein the second metaatom differs from the first metaatom in refractive index, and wherein the first metaatom has the same material composition as a material composition of the substrate.
  2. 2 . The optical element according to claim 1 , wherein the first metaatom is formed continuously from the substrate.
  3. 3 . The optical element according to claim 2 , wherein the first metaatom is a processed form of the substrate.
  4. 4 . The optical element according to claim 1 , wherein the metasurface includes a medium through which light is capable of propagating, and wherein the medium differs from the first metaatom and the second metaatom in refractive index.
  5. 5 . The optical element according to claim 4 , wherein the metasurface includes a void portion, and wherein the medium is air filling the void portion.
  6. 6 . The optical element according to claim 1 , wherein the first metaatom and the second metaatom each have a pillar structure.
  7. 7 . The optical element according to claim 1 , wherein the substrate contains at least one type of oxide out of oxides of La, Nb, W, Ti, K, Na, and Li.
  8. 8 . The optical element according to claim 1 , wherein the substrate is a resin containing cycloolefin or a resin containing polyolefin.
  9. 9 . The optical element according to claim 1 , wherein the substrate has a transmittance of 60% or more with respect to light having a wavelength of 400 nm or more and 800 nm or less.
  10. 10 . The optical element according to claim 1 , wherein the substrate contains at least one type out of polycrystalline silicon, Ge, ZnSe, SeS, ZnS, CaF 2 , sapphire, and chalcogenide glass.
  11. 11 . The optical element according to claim 1 , wherein the substrate contains at least one type of fluoride out of fluorides of Al, Mg, Ca, Ba, and Sr.
  12. 12 . The optical element according to claim 1 , wherein the substrate contains one of an oxide, a nitride, or an oxynitride of one type of element out of Si, Al, Ti, Hf, Ta, and Nb.
  13. 13 . The optical element according to claim 1 , wherein the substrate includes: a first substrate; and a second substrate placed so as to oppose the first substrate, wherein the metasurface is formed between the first substrate and the second substrate, wherein the first metaatom is formed on a surface of the first substrate that is opposed to the second substrate, wherein the second metaatom is formed on a surface of the second substrate that is opposed to the first substrate, wherein the first metaatom has the same material composition as a material composition of the first substrate, and wherein the second metaatom has the same material composition as a material composition of the second substrate.
  14. 14 . The optical element according to claim 13 , wherein the first metaatom is formed continuously from the first substrate.
  15. 15 . The optical element according to claim 13 , wherein the second metaatom is formed continuously from the second substrate.
  16. 16 . The optical element according to claim 13 , wherein the metasurface includes a third metaatom formed on a surface of one of the first substrate or the second substrate, and wherein the third metaatom has a material composition different from the material compositions of the first substrate and the second substrate.
  17. 17 . The optical element according to claim 13 , wherein the first metasurface includes a low-refractive index medium through which light is capable of propagating, and wherein the low-refractive index medium is lower in refractive index with respect to light than the first metaatom and the second metaatom.
  18. 18 . The optical element according to claim 13 , wherein at least one of the first substrate and the second substrate has a functional film on a surface on an opposite side from the metasurface.
  19. 19 . An optical element comprising a metasurface, wherein the metasurface includes a solid medium through which light is capable of propagating, wherein the solid medium includes, at least, a first metaatom, a second metaatom, and a third metaatom, wherein the first metaatom, the second metaatom, and the third metaatom differs from one another in refractive index, and wherein the first metaatom contains one of a silicon oxide or a metal oxide, or is a plastic resin.
  20. 20 . The optical element according to claim 19 , wherein the first metaatom contains at least one type of oxide out of oxides of Si, La, Nb, W, Ti, K, Na, and Li, or is one of a resin containing cycloolefin or a resin containing polyolefin.

Description

BACKGROUND Field of the Technology The present disclosure relates to an optical element and a method of manufacturing an optical element. Description of the Related Art Various apparatuses such as mirrorless cameras, smartphones, microscopes, and semiconductor exposure apparatus have optical systems for condensing desired light. Those optical systems use various lenses. The optical systems using those lenses have an optical design that uses a plurality of lenses to accomplish highly precise light condensation in which various aberrations are corrected. In recent years, mirrorless cameras, smartphones, and other such apparatuses have been demanded to be even smaller in size. However, in existing optical systems which use lenses to condense light through refraction of light by a curved surface shape and a refractive index of a medium, there is a limit to reduction of an optical system size and, accordingly, highly precise light condensation in which various aberrations are corrected and downsizing of the optical system have a trade-off relationship. Japanese Patent Laid-Open No. 2021-71727 addresses this issue and states that, by adopting an optical system configuration that combines a refractive lens with an optical element having a metasurface, thickness reduction of the optical system and solving of aberration problems are achieved. However, optical elements of the related art that have a metasurface have a low degree of freedom in designing of a metasurface. There is a wide range of needs for optical elements having a metasurface, and improvement of the degree of freedom in designing of a metasurface is accordingly demanded. SUMMARY Thus, the present disclosure is directed to an optical element and a method of manufacturing an optical element with which the degree of freedom in designing of a metasurface can be improved. According to one aspect of the present disclosure, there is provided an optical element including: a substrate; and a metasurface formed on the substrate, wherein the metasurface includes a first metaatom through which light is capable of propagating, and a second metaatom through which light is capable of propagating, wherein the second metaatom differs from the first metaatom in refractive index, and wherein the first metaatom has the same material composition as a material composition of the substrate. According to another aspect of the present disclosure, there is provided a method of manufacturing an optical element, including: forming a first metaatom on a surface of a substrate by processing the surface; and forming a second metaatom different from the first metaatom in refractive index, on the substrate with the first metaatom formed thereon. According to still another aspect of the present disclosure, there is provided an optical element including a metasurface, the metasurface including a solid medium through which light is capable of propagating, the solid medium including, at least, a first metaatom, a second metaatom, and a third metaatom, the first metaatom, the second metaatom, and the third metaatom differing from one another in refractive index, the first metaatom containing one of a silicon oxide or a metal oxide, or being a plastic resin. According to yet another aspect of the present disclosure, there is provided a method of manufacturing an optical element, including: forming a first metaatom on a surface of a substrate by processing the surface; forming a second metaatom different from the first metaatom in refractive index, on the surface with the first metaatom formed thereon; and forming a third metaatom different from the first metaatom and the second metaatom in refractive index, on the surface with the first metaatom and the second metaatom formed thereon. Features of the present disclosure will become apparent from the following description of embodiments with reference to the attached drawings. The following description of embodiments is described by way of example. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1A is a perspective view for illustrating an optical element according to a first embodiment of the present disclosure. FIG. 1B is a sectional view for illustrating the optical element according to the first embodiment of the present disclosure. FIG. 2 is a flow chart for illustrating steps of a method of manufacturing the optical element according to the first embodiment of the present disclosure. FIG. 3A is a sectional view for illustrating a step of the method of manufacturing the optical element according to the first embodiment of the present disclosure. FIG. 3B is a sectional view for illustrating a step of the method of manufacturing the optical element according to the first embodiment of the present disclosure. FIG. 3C is a sectional view for illustrating a step of the method of manufacturing the optical element according to the first embodiment of the present disclosure. FIG. 3D is a sectional view for illustrating a step of the method of manufactur