基于低相干光平面波照明的数字全息显微测量

Digital holographic microscopy illuminated by low-coherent plane waves

提出将基于低相干光平面波照明的离轴数字全息显微方法应用于微纳表面测量,结合角谱算法,可在更近的距离以高分辨率重建由平面波记录的数字全息图.在发光二极管平面波照明全息实验中,通过单幅离轴全息图对标准刻线板进行了强度像和相位像的重建.在重建过程中,未发生频谱重叠的现象.对其三维表面形貌的评定结果显示重建的横向参数值与纵向参数值均与标准值具有很好的一致性.

Off-axis digital holographic microscopy in mirco-nano surface measurement was proposed, which was based on the illumination of low coherent plane wave. Compared with sphere-wave inter- ferometry illuminated by lasers, low-coherent plane-wave interferometry could effectively avoid the influence of freckles and multiple-reflections. Combined with angular spectrum algorithm, digital holo- grams illuminated by plane wave could be reconstructed with smaller distances and higher resolutions. In the experiment illuminated by LED（light emitting diode）rs plane wave, the intensity-contrast and phase contrast images of a standard grating plate were reconstructed by a single off-axis hologram. Overlaps did not appear in the frequency spectrum during the reconstructed process. The evaluation of the three dimensional surface topography reveals that the reconstructed axial and lateral parameters are both in good accordance with their standard values.