利用白光作为光源的干涉仪(WLI)克服了单色相干光干涉相位不确定,不能够进行绝对测量的缺点,本文设计了一种串连差分白光干涉(DMLI)测量极薄金属带材厚度的新系统。该系统的特点是由两个迈克尔逊干涉仪(MI)串联组成差分干涉系统,两个干涉仪的测量反射面由薄带的两个对应表面承担,干涉系统的最后输出信号只与薄带的厚度有关,而与薄带在测量光路中的位置无关。理论分析及实验结果表明,该系统既有干涉测量的高精度、高灵敏度,又具有较强的抗干扰能力。

White Light Interferometry (WLI), overcoming the disadvantage of the phase ambiguity in the narrow-band interferometry, allowed absolute position determination. A new tandem differential white light interference system for the thickness measurement of metallic foil was designed. In this work, the differential white light system consists of two Michelson Interferometers (MI) in tandem. Reflective surfaces measured were the corresponding surfaces of metallic foil. Therefore, the measured result is only related to the thickness but not to the position of metal foil. Theoretical analysis and preliminary experimental results show that the method has advantages of high accuracy, fast detection and anti-interference.