An optical structure is presented. The optical structure includes a substrate including a cavity on a first surface of the substrate. The optical structure further includes an optical component on the substrate, the optical component including a second surface opposed to the first surface of the substrate. The optical structure also includes an adhesive in a gap between the first surface of the substrate and the second surface of the optical component affixing the optical component to the substrate, wherein at least one of the first surface of the substrate and the second surface of the optical component includes a predetermined portion arranged around the cavity, wherein the predetermined portion prevents the adhesive from infiltrating.