In the examples provided herein, an apparatus has a first substrate upon which one or more first filters have been fabricated on a first surface of the first substrate. The apparatus also has a second substrate upon which one or more second filters have been fabricated on a second surface of the second substrate, wherein the one or more first filters and the one or more second filters each transmit a different band of wavelengths. Additionally, the apparatus has a bonding material that bonds the first substrate to the second substrate.