An example device in accordance with an aspect of the present disclosure includes a slab to transmit light, and a plurality of lenses and filters disposed on first and second surfaces of the slab. The lenses include an anti-reflective coating on at least one of the plurality of lenses at an end of the slab to couple light through the anti-reflective coating, and a reflective coating disposed on remaining ones of the plurality of lenses to cause the lenses to reflect light. The filters are offset from the lenses to form an optical zig-zag.