CAJ | 학술논문

衍射光学元件被广泛应用于激光光束整形领域中。然而，在实际测量中常常发现衍射效率实际的测量值与设计值存在较大的偏差，原因之一在于输出的焦斑主瓣以外会产生高级次衍射杂散光。文中从理论上推导了高级次衍射杂散光产生的原因并对具有不同设计参数的衍射光学元件进行了仿真分析。通过研究，定义了一个新的参数，相对周期。它与光波波长成正比，与衍射光学元件的采样单元尺寸以及远场衍射角成反比。结果表明，衍射光学元件的衍射效率只是关于相对周期的函数，而与焦斑主瓣的具体形状无关。随着相对周期的增加，衍射效率随之增大。所以可通过适当选取远场衍射角和采样单元尺寸的参数以调整相对周期的大小，有效抑制高级次衍射杂散光。该参数在衍射元件的设计中具有重要的指导意义。
연사광학원건피엄범응용우격광광속정형영역중。연이，재실제측량중상상발현연사효솔실제적측량치여설계치존재교대적편차，원인지일재우수출적초반주판이외회산생고급차연사잡산광。문중종이론상추도료고급차연사잡산광산생적원인병대구유불동설계삼수적연사광학원건진행료방진분석。통과연구，정의료일개신적삼수，상대주기。타여광파파장성정비，여연사광학원건적채양단원척촌이급원장연사각성반비。결과표명，연사광학원건적연사효솔지시관우상대주기적함수，이여초반주판적구체형상무관。수착상대주기적증가，연사효솔수지증대。소이가통과괄당선취원장연사각화채양단원척촌적삼수이조정상대주기적대소，유효억제고급차연사잡산광。해삼수재연사원건적설계중구유중요적지도의의。
Diffractive optical elements (DOEs) have been widely applied to acquire different beam shapes in illumination systems. However, the experimental values of diffraction efficiency are greatly different from the ideal values because of stray light of high diffractive orders around the targeted spot. The reasons were theoretically discussed for the stray light and many DOEs with different design parameters were simulated. Through the simulation analysis, a new parameter, named relative period, was defined. It was proportional to the wavelength and inversely proportional to the far-field diffraction angle and the size of DOE cells. It is suggested that the diffraction efficiency, which is independent from the beam shapes, could be improved by increasing relative period. As a result, the stray light of high diffractive orders could be suppressed effectively by regulating the parameters of the far-field diffraction angle and the size of DOE cells. The new parameter has an important role in the design of DOE.