Eliminating Coherent Artifacts in Laser Interferometry

Coherent artifacts in interferometry can appear as bullseye patterns, speckles, and mottle caused by dust, scratches, and other factors. Controlling these artifacts is critical for high-resolution quantitative measurements. In this presentation, Damrau explains why coherent artifacts occur, how they affect precision measurements, and techniques for minimizing their influence on measurement results.

Even small changes to a measurement setup can shift the phase or shear of coherent artifacts, making them difficult to remove with error separation algorithms. Effective artifact reduction is therefore essential for achieving reliable, traceable interferometric measurements. By exploring the evolution of artifact reduction technologies, this presentation will highlight the advantages and limitations of different approaches and help attendees better understand their options for improving measurement quality.

About the presenter
William Damrau is Associate Product Manager for Laser Interferometers at Zygo, where he helps manage the company’s laser interferometer product line. He has nearly a decade of experience spanning mechanical engineering and product management, with a background in precision manufacturing, robotics and automation, product testing, and research.

Before joining Zygo, Damrau held engineering and product management roles supporting semiconductor manufacturing, laboratory automation, and other advanced technology applications. He earned a bachelor’s degree in mechanical engineering from the Georgia Institute of Technology, with a concentration in automation and robotics.