Synthesis and investigation of spectral, luminescence, and lasing properties of alumoborate crystals activated with chromium and neodymium ions

Crystals of compositions $Nd_xGd_{1-x}(Al_{1-y}Cr_y)_3(BO_3)_4$, were synthesized and investigated. A study was made of the spectral and luminescence characteristics of $Nd^{3+}$ and $Cr^{3+}$ ions in these crystals. The process of energy transfer from the $Cr^{3+}$ to the $Nd^{3+}$ ions was investigated. The spectral and luminescence properties were studied as a function of the $Cr$ concentration. Low-threshold stimulated emission at $\lambda=1,063\mu m$ was excited by laser radiation.