A microscope cube includes a housing including a first opening on a first wall of the housing and a second opening on a second wall of the housing, the first wall adjacent to the second wall; an excitation filter disposed within the first opening; an emission filter disposed within the second opening; and a dichroic mirror positioned within the housing. In one aspect, the dichroic mirror has a thickness greater than or equal to 1.5 mm. In another aspect, the excitation filter is positioned at an angle relative to the first wall of the housing.