Aspects of the invention include an optical housing including a substrate having a reflective side and an absorbing side. The substrate has a generally planar base portion and a protruding cover portion. The cover portion defines a pocket on the absorbing side. The substrate has an open position where the base portion is distal the cover and a closed position where the base portion is proximate the cover. The substrate is configured to enclosed a detector within the pocket in the closed position. The base portion defines an aperture generally centered within the base portion and aligned with the detector in the closed position so as to pass light through to the detector.