Optical tomography of residual stresses in GRIN rod lenses with transverse and longitudinal translucence

The residual stresses (RS) in gradient-index (GRIN) rod lens are formed due to the material characteristics gradient. RS can lead to the birefringence effect. If a GRIN lens is birefringent, its applications may be limited, because the anisotropy can cause the image quality degradation. According to this, the urgent task is to develop a non-destructive diagnostic method of RS in the gradient optical structures. This paper presents the relations of the generalized method of integral photoelasticity for reconstructions of RS (optical tomography of the stress field) for the case of the bending probing rays in GRIN optical rods with a radial distribution of the refractive index. The problem is solved with plane strain approximations. RS Distributions are given reconstructed from tomographic data obtained with transverse and longitudinal (coaxial) translucence of GRIN rod lens.