高斯光束经相位连续变化型波带片的衍射特性
Diffractive properties of terahertz zone plates with Gaussian beam incidence
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摘要: 根据瑞利-索末菲标量衍射理论分析了相位连续变化型波带片对高斯光束的衍射特性。在高斯光束入射下，对相位连续变化型波带片光轴和焦平面上的太赫兹强度分布特性进行了模拟，分析了入射光束的束腰半径和束腰位置对衍射场的影响，并与平面波入射的情况进行了对比。数值结果显示，相位连续变化型波带片可以实现对高斯分布太赫兹波的聚焦。相位连续变化型波带片的衍射规律与薄透镜的聚焦规律相似。通过合理调整束腰与波带片之间的距离可以保证衍射效率在85%以上。与平面波相比，高斯光束入射下的焦点处中心场强较小，但衍射效率较高。Abstract: Diffractive properties of the continuous phase type zone plate with Gaussian beam incidence were analyzed based on Rayleigh-Sommerfeld diffraction theory. The simulations of intensity distribution on the focal plane and the optic axis were completed using Matlab. Diffraction fields of the zone plate with continuous phase were analyzed. The effects of the parameters of the incident beam on the diffraction field were discussed. The results indicate that the continuous phase type zone plate can focus Gaussian beam with high diffraction efficiency. Diffraction law of the continuous phase type zone plate is similar to that of thin lens. If the waist location is optimized, the diffraction efficiency will be larger than 85%. Compared with the plane wave incidence, when the Gaussian beam is incide
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Key words:
- diffraction optics /
- terahertz /
- zone plates /
- continuous phase /
- gaussian beam
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