A curable liquid silicone composition, comprising: one or more types of organosilicon compound selected from the following component and component: an organosilane or organopolysiloxane having 1 to 5 silicon atoms, having at least two alkenyl groups with 2 to 12 carbon atoms in a molecule, and having at least one monovalent functional group selected from aromatic groups with 6 to 12 carbon atoms and aralkyl groups with 7 to 12 carbon atoms, and a chain or branched-chain organosilane or organopolysiloxane having 2 to 5 silicon atoms, having at least two alkenyl groups with 2 to 12 carbon atoms in a molecule, not having a monovalent functional group selected from aromatic groups with 6 to 12 carbon atoms and aralkyl groups with 7 to 12 carbon atoms, and having a boiling point at ambient pressure of 180°C or higher; a compound having at least two silicon-bonded hydrogen atoms in a molecule {at an amount where the silicon-bonded hydrogen atoms in the component are 0.2 to 3 mols relative to a total of 1 mol of alkenyl groups in the composition}; and a hydrosilylation reaction catalyst; wherein the refractive index at 25°C and a wavelength of 847 nm of the entire liquid composition prior to curing is 1.47 or more, and the viscosity of the entire liquid composition measured at 25°C using an E-type viscometer is 500 mPa·s or less. one or more types of organosilicon compound selected from the following component and component: an organosilane or organopolysiloxane having 1 to 5 silicon atoms, having at least two alkenyl groups with 2 to 12 carbon atoms in a molecule, and having at least one monovalent functional group selected from aromatic groups with 6 to 12 carbon atoms and aralkyl groups with 7 to 12 carbon atoms, and a chain or branched-chain organosilane or organopolysiloxane having 2 to 5 silicon atoms, having at least two alkenyl groups with 2 to 12 carbon atoms in a molecule, not having a monovalent functional group selected from aromatic groups with 6 to 12 carbon atoms and aralkyl groups with 7 to 12 carbon atoms, and having a boiling point at ambient pressure of 180°C or higher; a compound having at least two silicon-bonded hydrogen atoms in a molecule {at an amount where the silicon-bonded hydrogen atoms in the component are 0.2 to 3 mols relative to a total of 1 mol of alkenyl groups in the composition}; and a hydrosilylation reaction catalyst; wherein the refractive index at 25°C and a wavelength of 847 nm of the entire liquid composition prior to curing is 1.47 or more, and the viscosity of the entire liquid composition measured at 25°C using an E-type viscometer is 500 mPa·s or less. an organosilane or organopolysiloxane having 1 to 5 silicon atoms, having at least two alkenyl groups with 2 to 12 carbon atoms in a molecule, and having at least one monovalent functional group selected from aromatic groups with 6 to 12 carbon atoms and aralkyl groups with 7 to 12 carbon atoms, and a chain or branched-chain organosilane or organopolysiloxane having 2 to 5 silicon atoms, having at least two alkenyl groups with 2 to 12 carbon atoms in a molecule, not having a monovalent functional group selected from aromatic groups with 6 to 12 carbon atoms and aralkyl groups with 7 to 12 carbon atoms, and having a boiling point at ambient pressure of 180°C or higher; a compound having at least two silicon-bonded hydrogen atoms in a molecule {at an amount where the silicon-bonded hydrogen atoms in the component are 0.2 to 3 mols relative to a total of 1 mol of alkenyl groups in the composition}; and a hydrosilylation reaction catalyst; wherein