Dissertation Talk: Demultiplexed Mutiwavelength Interferometry for High Precision Metrology

Seminar | November 14 | 11 a.m.-12 p.m. | Soda Hall, 430 (Woz Lounge)

 Zain Zaidi

 Electrical Engineering and Computer Sciences (EECS)

Many areas of science and technology rely on the precise determination of distance over a sufficiently long range. Advanced ranging technology has the potential to open up a wide application field including 3D sensing, robotics and inspection for automated manufacturing, where high-precision, long-range, efficiency, and noise-tolerance are key. The small wavelength of light makes it a suitable candidate for precision metrology. A single wavelength interferometer has a high accuracy, but a small range that is limited by the ambiguous interferometric fringe order.

In this talk, I will present a new arithmetic algorithm for multiwavelength interferometer that has a theoretical maximum range of the lowest-common-multiple of the wavelengths used, the resolution of a single-wavelength interferometer, and the theoretical maximum noise tolerance of an algebraic approach. I will first describe the analytical formulation, analyze the noise tolerance, and present a recursive solution to extend the range through multiple wavelengths. To justify the practicality, experimental results from a simultaneous phase shifting demultiplexed two-wavelength interferometry system, with a range-resolution ratio of > 3e5, will then be presented to demonstrate the reliability of our method in the absence of any error correction.