X射线全息记录过程中影响分辨率的主要因素分析

分析了Ｘ射线全息记录过程中影响分辨率的一些主要因素。在完全相干的条件下，Ｘ射线无透镜傅里叶变换全息图的最小分辨距离不可能小于记录时用的Ｘ射线聚束器的焦斑或滤波小孔的半径，而Ｘ射线同轴全息图不可能获得比记录介质的截止频率更高的分辨率。在部分相干的条件下，Ｘ射线无透镜傅里叶变换全息所要求的相干长度和分辨率与样品半径成二次线型关系。Ｙ射线同轴全息所要求的相干长度和分辨率的平方以及样品到全息图的距离成正比，而与样品尺寸无关。随着Ｘ射线全息图分辨率的提高，其所要求的相干长度将大幅度增长。关键词：

ANALYSIS TO EFFECT OF MAIN FACTORS ON RESOLUTION INVOLVED IN X-RAY HOLO-GRAM RECORDING

Some main factors having influence on the resolution of X-ray holograms are analyzed theoretically. The smalles resolving distance of X-ray lensless Fourier transform holograms can not be less than the radius of the focus spot of the X-ray condenser or the filter aperture used in recording, and the resolution of X-ray in-line holograms can not be higher than the cutoff frequency of recording material, under the condition that X-ray is perfectly coherent. Relationships between the coherent length required by X-ray lensless Fourier transform holography and the resolution, and the radius of the object are quadric; and the coherent length requested by X-ray in-line holography is proportional to the square of the resolution and does not change with the size of object, under the condition that X-ray is partially coherent. With the resolution of X-ray holograms raised, the reguired coherent length will be increased by a large amount.