A polarization spectral filter (100; 200; 300; 400; 500; 600) comprising: a first reflector; a second reflector, the first reflector and the second reflector being disposed to face each other in a first direction; and a grating layer (120; 121) disposed between the first reflector and the secondreflector, wherein the grating layer comprises a plurality of first grating elements (120a; 121a) and a plurality of second grating elements (120b; 121b), the first grating elements (120a; 121a) and the second grating elements (120b; 121b) being alternately and repeatedly arranged with each other in a second direction perpendicular to the first direction, wherein each of the plurality of first grating elements (120a; 121a) includes a first dielectric material having a first refractive index, wherein each of the plurality of second grating elements (120b; 121b) includes a second dielectric material having a second refractive index different from the first refractive index, wherein the first reflector comprises a plurality of first dielectric layers and a plurality of second dielectric layers, the plurality of first dielectric layers and the plurality of second dielectric layers being alternately stacked with each other in a third direction, wherein the second reflector comprises a plurality of third dielectric layers and a plurality of fourth dielectric layers, the plurality of third dielectric layers and the plurality of fourth dielectric layers being alternately stacked with each other in the third direction, wherein each of the plurality of first dielectric layers includes a dielectric material having a refractive index that is different from a dielectric material included in each of the plurality of second dielectric layers, and wherein each of the plurality of third dielectric layers includes a dielectric material having a refractive index that is different from a dielectric material included in each of the plurality of fourth dielectric layers, the filter characterized in that each of the plurality of first dielectric layers and each of the plurality of third dielectric layers include the first dielectric material, and each of the plurality of second dielectric layers and each of the plurality of fourth dielectric layers include the second dielectric material. a first reflector; a second reflector, the first reflector and the second reflector being disposed to face each other in a first direction; and a grating layer (120; 121) disposed between the first reflector and the secondreflector, wherein the grating layer comprises a plurality of first grating elements (120a; 121a) and a plurality of second grating elements (120b; 121b), the first grating elements (120a; 121a) and the second grating elements (120b; 121b) being alternately and repeatedly arranged with each other in a second direction perpendicular to the first direction, wherein each of the plurality of first grating elements (120a; 121a) includes a first dielectric material having a first refractive index, wherein each of the plurality of second grating elements (120b; 121b) includes a second dielectric material having a second refractive index different from the first refractive index, wherein the first reflector comprises a plurality of first dielectric layers and a plurality of second dielectric layers, the plurality of first dielectric layers and the plurality of second dielectric layers being alternately stacked with each other in a third direction, wherein the second reflector comprises a plurality of third dielectric layers and a plurality of fourth dielectric layers, the plurality of third dielectric layers and the plurality of fourth dielectric layers being alternately stacked with each other in the third direction, wherein each of the plurality of first dielectric layers includes a dielectric material having a refractive index that is different from a dielectric material included in each of the plurality of second dielectric layers, and wherein each of the plurality of third dielectric layers includes a dielectric material having a refractive index that is different from a dielectric material included in each of the plurality of fourth dielectric layers, the filter characterized in that each of the plurality of first dielectric layers and each of the plurality of third dielectric layers include the first dielectric material, and each of the plurality of second dielectric layers and each of the plurality of fourth dielectric layers include the second dielectric material.