A semiconductor optical emitting device comprises an at least partially transparent substrate and an active semiconductor structure arranged on a first side of the substrate. A first portion of light generated by the active semiconductor structure is emitted through the substrate from the first side of the substrate to a second side of the substrate along a primary light emission path. The second side of the substrate has a groove formed therein with at least first and second surfaces configured to reflect respective additional portions of the light generated by the active semiconductor structure along respective first and second angled light emission paths. The first and second angled light emission paths may be in opposite directions to one another and substantially perpendicular to the primary light emission path, although numerous other light emission path arrangements are possible.