Abstract: This application relates to an optical sensor element. In one aspect, the optical sensor element includes a graphite column including one or more graphite rods. The optical sensor element may also include one or more first graphene layers partly or entirely covering each of both ends of the graphite column. The optical sensor element may further include one or more second graphene layers partly or entirely covering the outer circumferential surface of the graphite column. This application also relates to an optical sensor for measuring the concentration of a greenhouse gas and the optical sensor includes the optical sensor element.