Residual stress measurement methods of optics

Residual stress is an important performance indicator of optics, which is of great significance to the fabrications and applications of optical components. Residual stress measurement methods of optics can be summed up into two categories: methods based on the strain measurement and on the stress induced birefringence measurement, respectively. The strain based methods, which are built upon crystal dynamics and elastic mechanics, including X-ray diffraction (XRD), Stoney curvature method, and micro-Raman spectroscopic method, are well developed and widely used. Methods based on the measurements of birefringence phase retardation induced by residual stress, including digital photoelasticity method, photoelasticitic modulator (PEM) method and polarization-dependent cavity ring-down method, show a higher precision. The principles, measurement precisions and application scenarios of these residual stress measurement methods are summarized in this overview. Comparisons between the performances of these methods are performed and correlations between them are analyzed in detail.