Line-scan spectrum-encoded imaging by dual-comb interferometry
Posted: 2018-07-19   Author: 王玲   Views: 76

Herein, the method of spectrum-encoded dual-comb interferometry is introduced to measure a three-dimensional (3-D) profile with absolute distance information. By combining spectral encoding for wavelength-to-space mapping, dual-comb interferometry for decoding and optical reference for calibration, this system can obtain a 3-D profile of an object at a stand-off distance of 114 mm with a depth
precision of 12 μm. With the help of the reference arm, the absolute distance, reflectivity distribution, and depth information are simultaneously measured at a 5 kHz line-scan rate with free-running carrier-envelope offset frequencies. To verify the concept, experiments are conducted with multiple objects, including a resolution test chart, a three-stair structure, and a designed “ECNU” letter chain. The results show a horizontal resolution of ∼22 μm and a measurement range of 1.93 mm.

  

 

1 双光学频率梳3D快速成像实验装置图

  

  

 

2 a)三台阶样品的3D形貌图;(b)对应(a)图中白色虚线的一维深度曲线,插图为样品实物图;“ECNU”刻蚀字体的(c2D反射率图和(d3D形貌图

  

  

Opt. Lett. 43,1606(2018).pdf