“…Both BGO and BSO crystals in their undoped form are well-researched materials, (the first experiments were performed over 55 years ago on BGO in 1967 by Abrams S.C. et al [ 3 ]) with many practical applications [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 ], such as Pockels cells and sensors [ 1 , 3 ], phase-conjugated spatial-time light modulators [ 6 ], or holographic memory storage [ 13 , 14 , 15 , 16 ]. Over the last few years, doping of sillenites with transition-metal ions (e.g., Fe, Co, Cr or Cu) has been researched quite intensively with the goal of increasing the usefulness of BSO and BGO for holographic storage applications [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. In 2020, BGO crystals doped with Eu 3+ were successfully grown, which exhibited a strong luminescence in the yellow–red range of spectrum and could potentially be used as a laser material [ 25 ].…”