Diffractive optical element and optical system having the same
First Claim
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1. A diffractive optical element comprises three or more layers made of at least two kinds of materials of different dispersions, wherein a plurality of diffraction grating surfaces are formed at interfaces between adjacent layers, wherein each even-number-th layer has a uniform thickness, andwherein the materials of first and third layers are different from each other in the dispersion.
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Abstract
In a diffractive optical element composed of three or more laminated layers and having a diffraction grating at each interface between adjacent layers, each even-number-th layer has a uniform thickness.
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Citations
11 Claims
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1. A diffractive optical element comprises three or more layers made of at least two kinds of materials of different dispersions, wherein a plurality of diffraction grating surfaces are formed at interfaces between adjacent layers, wherein each even-number-th layer has a uniform thickness, and
wherein the materials of first and third layers are different from each other in the dispersion.
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2. A diffractive optical element comprises three or more layers made of at least two kinds of materials of different dispersions to enhance diffraction efficiency of a specific order over a wavelength region,
wherein, where said three or more layers are counted in order as an i-th layer, a plurality of diffraction grating surfaces are formed such that a first diffraction grating surface which is formed at a boundary between the first layer and the second layer, a second diffraction grating surface which is formed at a boundary between the second layer and the third layer, up through an L-th diffraction grating surface which is formed at a boundary between the L-th layer and the (L+1)-th layer, and each even-number-th layer is a layer having a uniform thickness over an entire area thereof, and wherein the materials of first and third layers are different from each other in the dispersion.
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