Resin composition, cured product, diffractive optical element, and multilayer diffractive optical element

A resin composition comprising:

• an indium tin oxide particle;
• and
• a near-ultraviolet light-absorbing organic compound,
• wherein the near-ultraviolet light-absorbing organic compound has a first wavelength of 340 nm to 400 nm, which first shows a maximum value in a case where an absorbance is measured from a wavelength of 800 nm,
• in a case where a maximum absorbance in a range of 340 nm to 400 nm is defined as Abs(λ max), an absorbance at a wavelength of 410 nm is defined as Abs(410 nm), and an absorbance at a wavelength of 430 nm is defined as Abs(430 nm), both the following two expressions are satisfied,
• (Abs(λ max)−Abs(410 nm))/Abs(max)≥0.97
• 1.00≥(Abs(max)−Abs(410 nm))/(Abs(λ max)−Abs(430 nm))≥0.97, and
• the near-ultraviolet light-absorbing organic compound is a compound represented by General Formula 1,
• Pol1-Sp1-L1-Ar-L2-Sp2-Pol2 (General Formula 1)
• in the formula, Ar is any one of aromatic ring groups represented by General Formulae 2-1 to 2-4,
• in the formulae, Q1 represents —S—, —O—, or NR11—, where R11 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms,
• Y1 represents an alkyl group having 1 to 6 carbon atoms, which may have a substituent, an aromatic hydrocarbon group having 6 to 12 carbon atoms, which may have a substituent, or an aromatic heterocyclic group having 3 to 12 carbon atoms, which may have a substituent,
• Z1, Z2, and Z3 each independently represent a hydrogen atom, an aliphatic hydrocarbon group having 1 to 20 carbon atoms, which may have a substituent, an alkoxy group having 1 to 20 carbon atoms, which may have a substituent, an alicyclic hydrocarbon group having 3 to 20 carbon atoms, which may have a substituent, a monovalent aromatic hydrocarbon group having 6 to 20 carbon atoms, which may have a substituent, a halogen atom, a cyano group, a nitro group, —NR12R13, or SR12, where Z1 and Z2 may be bonded to each other to form an aromatic hydrocarbon ring which may have a substituent or an aromatic hetero ring which may have a substituent, and R12 and R13 each independently represent a hydrogen atom or an alkyl group having 1 to 6 carbon atoms,
• A1 and A2 each independently represent a group selected from the group consisting of —O—, —NR21—, —S—, and CO—, where R21 represents a hydrogen atom or a substituent,
• X represents O, S, C to which a hydrogen atom or a substituent is bonded, or N to which a hydrogen atom or a substituent is bonded,
• Ax represents an organic group having 1 to 30 carbon atoms, which has at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic hetero ring, Ay represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, which may have a substituent, or an organic group having 1 to 30 carbon atoms, which has at least one aromatic ring selected from the group consisting of an aromatic hydrocarbon ring and an aromatic hetero ring, where the aromatic ring included in Ax and Ay may have a substituent, and Ax and Ay may be bonded to each other to form a ring which may have a substituent, and
• Q2 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, which may have a substituent,
• L1 and L2 each independently represent a single bond or a linking group selected from the group consisting of —O—, —S—, —C(═O)—, —OC(═O)—, —C(═O)O—, —OC(═O)O—, —NR101C(═O)—, —C(═O)NR102—, —OC(═O)NR103—, —NR104C(═O)O—, —SC(═O)—, and C(═O)S—, where R101, R102, R103, and R104 each independently represent -Sp3-Pol3 or a halogen atom,
• Sp1 and Sp2 each independently represent a single bond or a linking group selected from the group consisting of a linear alkylene group having 1 to 30 carbon atoms, which may have a substituent, and a group in which, in a linear alkylene group having 2 to 30 carbon atoms, which may have a substituent, one —CH2— or two or more —CH2—'s not adjacent to each other are replaced with —O—, —S—, —C(═O)—, —OC(═O)—, —C(═O)O—, —OC(═O)O—, —NR201C(═O)—, —C(═O)NR202—, —OC(═O)NR203—, —NR204C(═O)O—, —SC(═O)—, or —C(═O)S—, where R201, R202, R203, and R204 each independently represent -Sp4-Pol4 or a halogen atom, and Sp3 and Sp4 each independently represent a single bond or a divalent linking group, and
• Pol1, Pol2, Pol3, and Pol4 each independently represent a hydrogen atom or a polymerizable group,
• where the compound represented by General Formula 1 has at least one polymerizable group.