Dense Al2O3 condensates doped with ca. 1 at% Cr3+ in the gamma- and alpha-forms were synthesized by energetic Nd-YAG pulse laser ablation on clamped Al/Cr targets in oxygen. The analytical electron microscopic observations indicated the gamma-form was up to an abnormal large size of 2 mu m and the alpha-form several times larger in size. The two forms were under residual compressive stress up to several GPa according to room-temperature lattice parameters. Such a residual stress level was also indicated by the red shift of photoluminescence R-1 and R-2 lines for the as-formed alpha-condensates and the secondary alpha-phase due to gamma-delta-theta-alpha transformation upon 400 nm excitation at 2 mJ/pulse. The Al2O3:Cr3+ condensates are potential luminescence sensors of phase change and residual stress for industrial applications and may shed light on natural dynamic settings. (C) 2007 Elsevier B.V. All rights reserved.