Full-field measurement of residual stress in single-crystal diamond substrates based on Mueller matrix microscopy

In this work, a method has been proposed for fast-measuring full-field residual stress of diamond substrates based on Mueller Matrix (MM) microscopy. The measurement system features a polarization camera and a fixed compensator at 45 degrees orientation, and real-time birefringence imaging can be performed. The magnitude and orientation of residual stress have been characterized by the stress-optical law. Optical-grade synthetic diamond substrates after laser-cutting and grinding have been measured. After laser-cutting samples exhibit a central region where stress orientation is shifted by- 90 degrees from the x-axis. After double-sided fine grinding, the average stress value is relatively low at 0.094 GPa, while single-sided fine grinding yields average stress of 0.142 Gpa, whereas double-sided rough grinding leads to 0.157 Gpa. Full-field stress distributions obtained from Raman images show consistent patterns. The research indicates that the MM-based method is a promising technique for detecting diamond substrate birefringence and characterizing its stress variation during fabrication.