Optical element and optical design method

An optical design method for designing an optical element comprising a metalens having a finely shaped surface on which a fine pattern is formed based on a shape of a meta-atom and a bonded surface formed in a flat shape, and a bonding lens having a feature equivalent to an existing lens and being bonded to the bonded surface, the method comprising:

• a first restrictive condition step of identifying conditions for a diffractive optical element and the bonding lens that satisfy:
• B
• ⁢
• 1
• ∝
• λ
• 0
• (
• N
• ⁢
• 1
• -
• N
• ⁢
• 2
• )
• /
• (
• R
• ×
• (
• λ
• 1
• -
• λ
• 2
• )
• )
• ,
• wherein:
• B1 is a phase coefficient used to model the diffractive optical element by an equivalent refraction method using optical design software;
• λ0 is a normalized wavelength of the diffractive optical element;
• λ1 is a first correction target wavelength to be subjected to axial chromatic aberration correction;
• λ2 is a second correction target wavelength to be subjected to axial chromatic aberration correction;
• N1 is a first refractive index of the bonding lens for the first correction target wavelength;
• N2 is a second refractive index of the bonding lens for the second correction target wavelength;
• and
• R is a radius of curvature of a convex surface of the bonding lens.

An optical design method for designing an optical element comprising a metalens having a finely shaped surface on which a fine pattern is formed based on a shape of a meta-atom and a bonded surface formed in a flat shape, and a bonding lens having a feature equivalent to an existing lens and being bonded to the bonded surface, the method comprising:

• a second restrictive condition step of identifying conditions for a diffractive optical element and the bonding lens that satisfy:
• B
• ⁢
• 1
• ∝
• λ
• 0
• (
• φ
• p
• ⁢
• c
• ⁢
• 2
• -
• φ
• p
• ⁢
• c
• ⁢
• 1
• )
• /
• (
• -
• λ
• 1
• (
• 1
• -
• e
• ′
• ⁢
• φ
• pc
• ⁢
• 1
• )
• +
• λ
• 2
• (
• 1
• -
• e
• ′
• ⁢
• φ
• p
• ⁢
• c
• ⁢
• 2
• )
• )
• ,
• wherein:
• B1 is a phase coefficient used to model the diffractive optical element by an equivalent refraction method using optical design software;
• λ0 is a normalized wavelength of the diffractive optical element;
• λ1 is a first correction target wavelength to be subjected to axial chromatic aberration correction;
• λ2 is a second correction target wavelength to be subjected to axial chromatic aberration correction;
• φpc1 is a reciprocal of focal length of the bonding lens;
• φpc2 is a reciprocal of focal length of the diffractive optical element;
• and
• e′ is a geometric optical distance between the diffractive optical element and the bonding lens.