像面数字全息显微系统的成像分辨率及成像特点

Resolution and characteristics of an image-plane digital holographic microscopic system

为了实现高质量成像,通过对实际的像面数字全息显微系统(IPDHMS)点扩散函数的推导,分析了系统的成像分辨率决定因素及成像特点,给出了相应的实验结果。结果表明,IPDHMS的成像分辨率取决于显微物镜(MO)的成像分辨率和记录器件的像元大小,而与记录器件的光敏面尺寸无关;无论物体被照亮区域有多大,对全息图的记录和再现都没有影响;IPDHMS对成像区域中各点发出的通过MO的各种频率成分均能完整记录与再现,是一种优化的全息成像系统,利用该系统可以实现高质量成像与测量。实验结果证明了理论分析的正确性。

In order to improve image quality, the point spread functions of practical image-plane digital holographic microscopic system （IPDHMS） with both spherical and plane reference waves are derived. The imaging resolution and imaging characteristics are analyzed. The corresponding experimental investi- gations are conducted. The results show that the imaging resolution of IPDHMS depends on the imaging resolution of the microscopic objective （MO） and the pixel size,but independent of the photosensitive surface size of the CCD. The big size of the illuminated region of the test sample doesn＇t affect the re- cording and the numerical reconstruction of the hologram. All frequency components that pass through the MO of each point in the imaging area can be completely recorded and reconstructed. IPDHMS is an optimized holographic imaging system,which can achieve high-quality imaging. The experimental results demonstrate the validity of theoretical analysis.