Abstract: An optical glass containing Si, Al, Ca, and O is provided. The optical glass contains Si in an amount of 7% or more and 93% or less, in cation percent, Al in an amount of 2% or more and 57% or less, in cation percent, and Ca in an amount of 2% or more and 52% or less, in cation percent. In the optical glass, a total amount of Si, Al, and Ca is 99.5% or more, in cation percent. Further, the optical glass contains Fe and Na each in an amount of 0.01 wtppm or less and has a transmittance to a light having a wavelength of 248 nm of 15% or more at a thickness of 5 mm.

Abstract: An optical glass that contains Si, Al, Mg, and O is provided. The optical glass contains Si in an amount of 40% or more and 60% or less, in cation percent, Al in an amount of 10% or more and 35% or less, in cation percent, and Mg in an amount of 20% or more and 35% or less, in cation percent. In the optical glass, the total amount of Si, Al, and Mg is 99.5% or more, in cation percent. Furthermore, the optical glass contains Fe and Na each in an amount of 0.01 wtppm or less and has a transmittance to a light having a wavelength of 248 nm of 40% or more at a thickness of 5 mm.