Note: Error elimination for ellipsometry by laser feedback instrument

Abstract

Ellipsometry has in recent decades been used in measuring optical phase retardation. Known for its high resolution but uncertain accuracy, we analyze the systematic error involved with this technique and give error values regarding phase retardation measurements. We developed a laser-feedback assembly to measure phase retardation to a higher resolution and accuracy compared with that from ellipsometry. We eliminated the systematic error associated with ellipsometry using results obtained with this assembly and improved measurement accuracies for ellipsometry to about 0.2°. Such high-precision ellipsometry would greatly improve the manufacturing of wave plates.