Two α‐SiO2‐Related Deep‐Ultraviolet Phase‐Matchable Optical Nonlinear Beryllium Silicate Crystals Na2BeSiO4 and Li2BeSiO4 with Enhanced SHG Effect

Deep-UV, (wavelength λ < 200 nm) nonlinear-optical (NLO) silicate crystals have long been troubled by weak second-harmonic-generation (SHG) effect and common non-phase-matchability, leading to the stagnation of silicate research, despite abundant reserves of silicates on the earth. Representative and simple α-SiO