Design Of The Binary Optical Element Of Long Focal Depth And Small Spot

In the traditional optics, there is a contradiction between focal depth and focal spot. An optical system couldn't achieve the effect of large focal depth and small focal spot, so the applications of this performance are restricted very much in laser domain. Binary optic technology (BOT) is a hotspot in the international optic discussion, which bases on the diffraction theory of light wave. and uses the accessorial design of computer. Compared with traditional optics, binary optical element (BOE) could modulate wave-front when light waves are incidence, and change the phase, so as to get the relevant distribution of the output of light waves. This paper researches the design of long focal depth and small focal spot with analyzing the theory, simulating the results with computer and designing the profile of BOE. The content of this paper is as follows:First, it is introduced that there is a contradiction between focal depth and focal spot, and the principle of design of BOE which have the performance of extended focal depth. And then the various kinds of methods of design are mentioned, which involve changing the numeric aperture, axicon and PSM method in the first moment. In the next moment there are several design plans such as diffraction-free beams and the method of conversation of energy. After that, the author introduces the birth and development of binary optics and the actuality of designing optical elements with long focal depth and small spot.Second, it is discussed that how to carry out the performance, and complete the programme of BOE's phase function with long focal depth and small spot. And then the paper simulate the design result and validate the phase function, which get the optical intensity and spot dimension of output planes within objective focal depth. Then the author At last, composes the phase function of BOE, and gets the expression.Third, the paper writes the programme of ZEMAX and VC++, and obtains the surface profile of designed phase function. At last, it is tested and proves that the surface profile is the right result. The paper combines the BOT and the performance of long focal depth and small spot together to probe into the design method, and completes the founded research of the task, which supply some profitable help and use for reference.