A display device includes a diffractive optical element and a tunable light source operable in different states including a first state and a second state. The tunable light source provides first light having a first wavelength while the tunable light source is in the first state and second light having a second wavelength, distinct from the first wavelength, while the tunable light source is in the second state. The first wavelength and the second wavelength correspond to a first color band. The diffractive optical element is positioned to receive and redirect the first light and receive and redirect the second light. The diffractive optical element has a first focal length for the first light and a second focal length, distinct from the first focal length, for the second light.