Abstract: The optical element of the present invention has an anti-reflection film formed on a substrate. Here, the anti-reflection film comprises a first layer formed on the substrate; a second layer formed on the first layer and consisting of a material different from that of the first layer; and a third layer formed on the second layer and consisting of a concave-convex structure. Also, the third layer has three regions of which a refractive index for each thickness changes at a constant rate by continuously changing the space filling factor of the concave-convex structure.

Abstract: The optical element of the present invention has an anti-reflection film formed on a substrate. Here, the anti-reflection film comprises a first layer formed on the substrate; a second layer formed on the first layer and consisting of a material different from that of the first layer; and a third layer formed on the second layer and consisting of a concave-convex structure. Also, the third layer has three regions of which a refractive index for each thickness changes at a constant rate by continuously changing the space filling factor of the concave-convex structure.

Abstract: An optical element includes a transparent substrate and an antireflection coating on the substrate. The antireflection coating includes an intermediate layer on the substrate, and an undulation layer that is formed on the intermediate layer and has a plurality of convexes arrayed with spacing shorter than a shortest wavelength. The undulation layer has a portion where refractive index increases from a light incident side to the substrate. The intermediate layer has a first layer closest to the substrate, and a second layer formed on the first layer. A refractive index n1 of the first layer, a refractive index n2 of the second layer, and a refractive index ns of the substrate satisfy the following conditional equations: 1.75?ns?2.20; n1<n2; and n1<ns.

Abstract: The polarization beam splitting element is configured to reflect or transmit an entering beam according to its polarization direction. The element includes, in order from a beam entrance side, a base member having a light transmissive property, a first one-dimensional grating structure formed of a dielectric material and having, in a first direction, a first grating period smaller than a wavelength of the entering beam, and a second one-dimensional grating structure formed of a metal and having, in a second direction orthogonal to the first direction, a second grating period smaller than the wavelength of the entering beam.

Abstract: The polarization beam splitting element splits an entering beam according to polarization directions. The element includes, in order from a beam entrance side, an entrance side multi-layered film layer constituted by laminated multiple dielectric films, and a one-dimensional grating structure having a grating period smaller than a wavelength of the entering beam and formed of a metal. When a medium existing on the beam entrance side further than the entrance side multi-layered film layer is referred to as an entrance medium, the multiple dielectric films constituting the entrance side multi-layered film layer include at least one dielectric film having a higher refractive index than that of the entrance medium and at least one dielectric film having a lower refractive index than that of the entrance medium.

Abstract: An optical element includes a transparent substrate and an antireflection coating on the substrate. The antireflection coating includes an intermediate layer on the substrate, and an undulation layer that is formed on the intermediate layer and has a plurality of convexes arrayed with spacing shorter than a shortest wavelength. The undulation layer has a portion where refractive index increases from a light incident side to the substrate. The intermediate layer has a first layer closest to the substrate, and a second layer formed on the first layer. A refractive index n1 of the first layer, a refractive index n2 of the second layer, and a refractive index ns of the substrate satisfy the following conditional equations: 1.75?ns?2.20; n1<n2; and n1<ns.

Abstract: The polarization beam splitting element includes a one-dimensional grating structure having a grating period smaller than a wavelength of an entering beam and including a metal grating portion, and two light-transmissive members each having a refractive index higher than that of air. The one-dimensional grating structure is disposed between the two light-transmissive members. The grating period of the one-dimensional grating structure is 120 nm or less, a thickness of the one-dimensional grating structure is 100 nm or less and an inter-grating portion of the one-dimensional grating structure is formed as a vacuum space or formed of air or a dielectric material. The grating period ? [nm], a filling factor FF that is a ratio w/? of a width w [nm] of the grating portion to the grating period, a refractive index na of the inter-grating portion and a wavelength ?g of 550 [nm] satisfy (1.4na?2.9)?/?g?0.57na+1.32?FF?(1.4na?2.9)?/?g?0.57na+1.39 and 0.152np?1.375(?/?g)+0.5?FF?0.152np?1.375(?/?g)+0.6.

Abstract: The optical element of the present invention has an anti-reflection film formed on a substrate. Here, the anti-reflection film comprises a first layer formed on the substrate; a second layer formed on the first layer and consisting of a material different from that of the first layer; and a third layer formed on the second layer and consisting of a concave-convex structure. Also, the third layer has three regions of which a refractive index for each thickness changes at a constant rate by continuously changing the space filling factor of the concave-convex structure.

Abstract: The polarization beam splitting element is configured to reflect or transmit an entering beam according to its polarization direction. The element includes, in order from a beam entrance side, a base member having a light transmissive property, a first one-dimensional grating structure formed of a dielectric material and having, in a first direction, a first grating period smaller than a wavelength of the entering beam, and a second one-dimensional grating structure formed of a metal and having, in a second direction orthogonal to the first direction, a second grating period smaller than the wavelength of the entering beam.

Abstract: The polarization beam splitting element splits an entering beam according to polarization directions. The element includes, in order from a beam entrance side, an entrance side multi-layered film layer constituted by laminated multiple dielectric films, and a one-dimensional grating structure having a grating period smaller than a wavelength of the entering beam and formed of a metal. When a medium existing on the beam entrance side further than the entrance side multi-layered film layer is referred to as an entrance medium, the multiple dielectric films constituting the entrance side multi-layered film layer include at least one dielectric film having a higher refractive index than that of the entrance medium and at least one dielectric film having a lower refractive index than that of the entrance medium.

Abstract: The polarization beam splitting element includes a one-dimensional grating structure having a grating period smaller than a wavelength of an entering beam and including a metal grating portion, and two light-transmissive members each having a refractive index higher than that of air. The one-dimensional grating structure is disposed between the two light-transmissive members. The grating period of the one-dimensional grating structure is 120 nm or less, a thickness of the one-dimensional grating structure is 100 nm or less and an inter-grating portion of the one-dimensional grating structure is formed as a vacuum space or formed of air or a dielectric material. The grating period ? [nm], a filling factor FF that is a ratio w/? of a width w [nm] of the grating portion to the grating period, a refractive index na of the inter-grating portion and a wavelength ?g of 550 [nm] satisfy (1.4na?2.9)?/?g?0.57na+1.32?FF?(1.4na?2.9)?/?g?0.57na+1.39 and 0.152np?1.375(?/?g)+0.5?FF?0.152np?1.375(?/?g)+0.6.