DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The current invention provides an arrangement of a holographic light that produces repetitive objects in space using Talbot-Lau method of self-imaging.
Figure1 shows the schematic details of the lighting structure, describing the comprehensive details of the total operation. A LED light source 10 is placed at the front focal plane of the lens 11, in order to provide an approximately parallel beam of light of a particular wavelength?.13 is a computer generated hologram placed on hologram plane 12in an off-axis fashion. This hologram when illuminated with parallel light of wavelength ?,it produces a 3D pattern 15 a few centimeters away5 on plane 14. On the same plane 14 a 3D comb function 16 (i.e. an array of 2D comb functions with proper alignment) is also placed on the other side of the optical axis27. The comb function has the period a.Plane 14 is situated at the front-focal plane of lens 17. Therefore, on its back-focal plane 18, we get the on-axis structure 19, which is the multiplication of the Fourier Transfroms of the holographic structure and the comb function. Plane 18 is again situated at the front-focal plane of next lens 20. Therefore, on the back-focal plane 21 of lens 20, we get the convolution of the two 3D structures 15 and 16, giving the new structure 22. Another 3D comb structure 24, same as that of the first one16, is to be placed axially on plane 23. Plane 23 is away from plane 21 by a distance of z_0=na^2/?. After this following Talbot-Lau effect we get repetitive self-reconstructions of the periodic structure 22 in space at 25 and 26.

Figure2 shows the arrangements of the components only and their positioning. Seven components are needed to build the total lighting structure, namely, one monochromatic LED light 10, three positive lenses 11, 17 and 20 – may be of equal focal length f ; one computer-generated-hologram 13 and two identical 3D comb structures 16 and 24. Distance of 10 and 11 is ~f. Again distances between plane 14 and lens 17, lens 17 and plane 18, plane 18 and lens 20, and lens 20 and plane 21 is also f. The holographic element 13 and comb function 16 is to be placed on the opposite halves of optical axis 27. The distance of plane 12 and plane 14 should be such that, the holographic element 13 generates the 3D hologram on 14. The other comb structure 24 is to be placed on axis at plane 23. The distance between 21 and 23 is z_0=na^2/?.
,CLAIMS:1. A holographic lighting structure comprising a monochromatic LED source, a holographic element for 3D pattern generation and two 3D comb structures to make the pattern periodic and propagate it in space.
2. The illumination to the holographic element is provided with a LED placed at front-focal plane of a lens.
3. The holographic element is a computer-generated-hologram with phase-only structure.
4. The 3D holographic pattern is made periodic with the help of a 3D comb structure along with two Fourier transforming lenses.
5. Another comb structure, identical to the first one, is to be used to produce Talbot-Lau effect in space.