提出使用飞秒激光器的光学频率梳测量绝对距离的方法。将一个飞秒激光器作为绝对距离测量的光源, 搭建迈克尔逊干涉结构, 利用色散干涉原理进行相应的光谱分析, 得到干涉光路的光学路径差引起的相位差, 最终计算出干涉光路的光学路径差。实验结果表明我们的长度测量方法精确度高, 分辨力达到纳米量级。最小测量距离达到 9 μm, 非模糊范围达到 5.75 mm。相对于传统白光色散干涉技术的有限测量范围, 最大测量距离可以扩展到任意长度。

The method of measuring absolute distance with the optical frequency comb of a femtosecond laser was proposed. A femtosecond laser was used as the light source of performing absolute distance measurement. A Michelson type interferometer structure was built. Exploiting the principle of the dispersive interference, the spectrum was analyzed. Then, the phase difference which was caused by the optical path difference of optical interference was obtained. Finally, the optical path length difference was measured. The experiment result shows that our length measurement method has high accuracy with the resolution of nanometer level. The minimum measurable distance is 9 μm, and the non-ambiguity range of length measurement is 5.75 mm. Compared to the limited measuring range of traditional white light interferometry, the maximum distance can be extended to arbitrary length.