| Abstract: | The design of a new optical element is reported. Based on the energy conservation theory and the binary optical fabrication technology, it is designed and fabricated a binary optical element (BOE) with extreme long focal depth. When the plane wave passes the element, it is transformed into a non-diffractive beam behind the BOE. In the optical axis direction within 15-meter-long the non-diffractive beam can limit the spot diameter to less than 800 μm and the diffusion angle to less than 0.015 mrad. The quality of non-diffractive beam is better than the ordinary laser beam. As a creditable and convenient optical datum line, this beam can be used in fitting and aligning large dimension devices, long distance collimation measurement and other fields. |
