Zhang N, Davis Jeffrey A, Moreno Ignacio, Cottrell Don M, Yuan X-C
School of Electrical & Electronic Engineering, Nanyang Technological University, 639798 Singapore.
Opt Express. 2010 Dec 6;18(25):25987-92. doi: 10.1364/OE.18.025987.
Optical vortices can be easily generated using a multilevel spiral phase plate (SPP). However the quality of the generated vortex beam depends on the number of phase segments. We review the theory for this multilevel SPP using a Fourier expansion of integer topological charged vortices. We then experimentally examine the validity of this expansion using a fabricated Dammann vortex diffraction grating spectrum analyzer. The Dammann vortex diffraction grating is fabricated using SU-8 photoresist on glass substrate and yields uniform diffraction efficiency across a desired number of diffracted orders. Experimental results show the extra angular harmonics of a multilevel SPP and agree with the theory.
使用多级螺旋相位板（SPP）可以轻松产生光学涡旋。然而，所产生的涡旋光束的质量取决于相位段的数量。我们使用整数拓扑电荷涡旋的傅里叶展开来回顾这种多级SPP的理论。然后，我们使用制造的达曼涡旋衍射光栅光谱分析仪通过实验检验这种展开的有效性。达曼涡旋衍射光栅是在玻璃基板上使用SU-8光刻胶制造的，并且在所需数量的衍射级上产生均匀的衍射效率。实验结果显示了多级SPP的额外角谐波，并且与理论相符。
