菲涅耳波带板无运动卷积偏振选通成像研究

提出了菲涅耳波带板(FZP)无运动卷积偏振选通全息术,该技术的原理与菲涅耳波带板扫描全息术相同,但在成像系统结构上作了重大改进,改进内容主要有两个方面:第一,使用扩展光源,用多个菲涅耳波带板在物体上的投影叠加形成卷积运算来取代机械扫描,克服了扫描造成的系统不稳定性和限制实际应用的耗时问题;第二,用CCD取代光电倍增管,使物体上所有的点都同时成像在CCD靶面上,达到实时采集整个全息图的目的。对线偏振光和圆偏振光经过散射介质脂肪乳剂(Intralipid)溶液后偏振度的变化规律进行了实验研究,研究表明,在米氏散射区,圆偏振光比线偏振光更容易保持偏振态。应用菲涅耳波带板无运动卷积偏振选通成像系统,采用圆偏振光作为入射光,对嵌埋在浓度为1%、深度为2 cm的脂肪乳剂溶液中的金属丝(直径0.4 mm)进行了成像实验,结果表明,菲涅耳波带板无运动卷积偏振选通全息术原理是可行的。

Study on Polarization-Based Holography of Fresnel Zone Plate Convolution without Motion

The polarization-based holography of Fresnel zone plate(FZP) convolution without motion is proposed.Its principle is the same as that of the FZP scanning holography.But its configuration is modified significantly.First,the uniformly distributed source is used to form the superposition of the FZP projects on the object so as to realize the convolution operation.Thus the time-consuming problem and the unstability of the system due to the mechanical scanning are resolved.Furthermore,the imaging system is more stable than before.Secondly,the CCD camera is used to replace the photomultiplier tube to collect the whole hologram in real time.The degree of polarization is investigated experimentally when the linearly and circularly polarized light propagate respectively through the scattering media of intralipid.The results demonstrate that the polarization of the circularly polarized light is maintained better than that of the linearly polarized light.By using of the imaging system of the polarization-based holography of FZP convolution without motion,the experiments on a metal wire with a diameter of 0.4 mm embedded in the intralipid solution with concentration of 1%(volume fraction) and depth of 2 cm are implemented.The experimental results testify the principle of polarization-based holography of FZP convolution without motion is feasible.