Optical transmission, dispersion, and transition behavior of ZnGa ₂ O ₄ transparent ceramic

Abstract

Abstract As an emerging transparent ceramic with extremely wide transmission range, the unique optical properties of ZnGa 2 O 4 are of particular interest. In this work, ZnGa 2 O 4 transparent ceramic with high optical quality was prepared by pressureless sintering and hot isostatic pressing. Its optical behavior was then comprehensively studied. The critical optical data, including refractive index, extinction coefficient, Abbé number, absorption coefficient in infrared region, and phonon frequency, were investigated. The indirect band gap and the phonon energy assisting indirect transition were determined as 4.10 and 0.17 eV, respectively. The modified Sellmeier equation and single‐oscillator dispersion relation were derived to describe the optical dispersion. Benefitting from the weaker tetrahedral Zn–O bond and heavier cationic masses, the infrared transmission range of ZnGa 2 O 4 transparent ceramic was broadened significantly. Oxygen vacancies were suggested to induce the absorption in lower photon energy region of ZnGa 2 O 4 transparent ceramic, which may enrich its functionalization. This work is meaningful for gaining overall insight into optical properties of transparent materials.