Non-Linear Optical Properties of the (RE)3CuGeS7 Family of Compounds

Abstract

Non-linear optical materials must possess a balanced combination of laser-induced damage threshold (LDT) and second-harmonic generation (SHG) and be phase matchable. In our previous work, chiral and polar La3CuGeS7 was identified as a promising non-linear optical material. Herein, we report the optimization of non-linear optical properties through replacement of La with smaller lanthanides. It is determined that Gd3CuGeS7 exhibits the best combination of SHG (1.6× AgGaS2 at 88–105 μm particle size) and LDT (3× AgGaS2, 89 MW/cm2) and is phase matchable. Based on changes in metal-sulfur bond lengths and angles, we further propose structural optimization through solid-solution formation and doping.