Surface-based luminescence measurement substrate

Surface-based measurement substrate including: • - at least one optical cavity layer (7); • - a first optical mirror (9) and a second optical mirror (11), the first and second optical mirrors enclosing the optical cavity layer and defining an optical cavity, wherein the first optical mirror and the second optical mirror are attached or fixed to the optical cavity layer to sandwich the optical cavity layer between the first and second mirrors; and • - an interface layer or interface coating (15) provided on the first mirror or the second mirror, the interface layer or coating being configured to receive or hold at least one entity (4) comprising at least one electromagnetic radiation emitting marker (3).