[摘要]:The changes of the optical power of Gradient Index (GRIN) lenses occurring in hydrostatic pressures of the range of 0-2 GPa are investigated. The measurements of the position of the waist of the semiconductor laser beam revealed the increase of the optical power of the lenses with increasing pressure. The use of the special piano-concave lenses insensitive to the changes of the refractive index of the pressure medium allowed to attribute the changes to the increasing index gradient in GRIN material. The effect has been explained within the frame of Mueller's theory of photoelasticity. The findings have been then confirmed in experiments with the piano-planar and piano-convex lenses of the same materials. (C) 2011 Elsevier B.V. All rights reserved.