The invention provides an imaging system comprising an optical element for deflecting axially incident light into a series of axially spaced outward radial projections, and further comprising an image collection means for collecting reflected light. The element comprises a plurality of light deflecting surfaces or features which are arranged at axially successive points along the element, each at a different radial location. The light-deflecting surfaces are arranged to deflect light incident upon them from an axial direction in a radial direction, each thereby generating a radial projection of light from the element. A beam or beam bundle projected along the element has successive outer annular layers stripped by the facets and deflected outwards at different axial points along the structure.

A light source device includes a first light source to provide a first input light beam in the direction of a central axis of the light source device, a second light source to provide a second input light beam in the direction of the central axis, a central reflector, a catadioptric reflector to focus light of the first input light beam to the central reflector, and to focus light of the second input light beam to the central reflector, and at least one actuator to change the angular position of the central reflector, so as to cause the central reflector to form an output beam by sequentially reflecting light of the first input light beam and light of the second input light beam to the axial direction.

A light source device includes a first light source to provide a first input light beam in the direction of a central axis of the light source device, a second light source to provide a second input light beam in the direction of the central axis, a central reflector, a catadioptric reflector to focus light of the first input light beam to the central reflector, and to focus light of the second input light beam to the central reflector, and at least one actuator to change the angular position of the central reflector, so as to cause the central reflector to form an output beam by sequentially reflecting light of the first input light beam and light of the second input light beam to the axial direction.

The invention provides an imaging system comprising an optical element for deflecting axially incident light into a series of axially spaced outward radial projections, and further comprising an image collection means for collecting reflected light. The element comprises a plurality of light deflecting surfaces or features which are arranged at axially successive points along the element, each at a different radial location. The light-deflecting surfaces are arranged to deflect light incident upon them from an axial direction in a radial direction, each thereby generating a radial projection of light from the element. A beam or beam bundle projected along the element has successive outer annular layers stripped by the facets and deflected outwards at different axial points along the structure.

An optical element of an embodiment includes an optical element made of a material transparent to light, the optical element including: a back surface facing the front surface; and a connection surface. The front surface includes a recessed surface in a region facing the connection surface. The recessed surface has a point closest to the connection surface as a closest point, and has a first singular point other than the closest point.