An optical apparatus comprising: a light source; and a beam scanning apparatus, adapted to scan light emitted from the light source, comprising a rotary lens comprising a transparent substrate having a disc shape, the lens comprising a plurality of areas (20a-20l) arranged in a circumferential direction of the substrate, and a rotation drive device configured to rotate the rotary lens; wherein a first area of the plurality of areas is configured to direct light transmitted therethrough to a first location within a scanning area and a second area of the plurality of areas is configured to direct light transmitted therethrough to a second location within the scanning area, different from the first location; characterized by a photodetector arranged to sense light emitted from the light source and reflected from an external object; in that the rotary lens is a rotary meta lens and the plurality of areas is a plurality of meta areas (20a-20l), each of the plurality of meta areas comprising a plurality of fine phase shift elements arranged therein; the interval between adjacent phase shift elements is less than the wavelengths of incident light from the light source; in that the plurality of meta areas are a plurality of inner meta areas, each disposed at a first radial distance (R2, R3) of the transparent substrate, and the rotary meta lens further comprises a plurality of outer meta areas, each disposed at a second radial distance (R2, R1) of the transparent substrate, different from the first radial distance of the transparent substrate; and in that the light source is radially movable to illuminate the meta areas at the different radial distances, or the light source comprises a separate light source (121a, 121b, 121c) arranged for each of the radial distances. a light source; and a beam scanning apparatus, adapted to scan light emitted from the light source, comprising a rotary lens comprising a transparent substrate having a disc shape, the lens comprising a plurality of areas (20a-20l) arranged in a circumferential direction of the substrate, and a rotation drive device configured to rotate the rotary lens; wherein a first area of the plurality of areas is configured to direct light transmitted therethrough to a first location within a scanning area and a second area of the plurality of areas is configured to direct light transmitted therethrough to a second location within the scanning area, different from the first location; characterized by a photodetector arranged to sense light emitted from the light source and reflected from an external object; in that the rotary lens is a rotary meta lens and the plurality of areas is a plurality of meta areas (20a-20l), each of the plurality of meta areas comprising a plurality of fine phase shift elements arranged therein; the interval between adjacent phase shift elements is less than the wavelengths of incident light from the light source; in that the plurality of meta areas are a plurality of inner meta areas, each disposed at a first radial distance (R2, R3) of the transparent substrate, and the rotary meta lens further comprises a plurality of outer meta areas, each disposed at a second radial distance (R2, R1) of the transparent substrate, different from the first radial distance of the transparent substrate; and in that the light source is radially movable to illuminate the meta areas at the different radial distances, or the light source comprises a separate light source (121a, 121b, 121c) arranged for each of the radial distances.