An experimental study is made of laser action in Dy**3** plus 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//1//2:Yb**3** plus :Dy**3** plus and BaY//2F//8:Dy**3** plus media.