Three-micron laser action in $Dy^{3+}$

An experimental investigation was made of laser action in $Dy^{3+}$ ions in an $LaF_3$ crystal excited by neodymium laser radiation. It is shown by calculation that neodymium laser radiation may be converted to the three-micron range with an efficiency of the order of $10\%$ using $Y_3Al_5O_{12}:Yb^{3+}-Dy^{3+}$ and $BaY_2F_8:Dy^{3+}$ media.