Laser activity at 1.18 um, 1.07 um, and 0.97 umin the low phonon energy crystalline hosts KPb2Br5 and RbPb2Br5 doped with Nd3+

For the first time laser activity has been achieved in the low phonon energy, moisture-resistant bromide host crystals, neodymium-doped potassium lead bromide (Nd{sup 3+}:KPb{sub 2}Br{sub 5}) and rubidium lead bromide (Nd{sup 3+}:RbPb{sub 2}Br{sub 5}). Laser activity at 1.07 {micro}m was observed for both crystalline materials. Laser operation at the new wavelengths 1.18 {micro}m and 0.97 {micro}m resulting from the {sup 4}F{sub 5/2} + {sup 2}H{sub 9/2} {yields} {sup 4}I{sub J} transitions (J=13/2 and 11/2) in Nd:RPB was achieved for the first time in a solid state laser material. Rare earth- doped MPb{sub 2}Br{sub 5} (M=K, Rb) is a promising candidate for long wavelength infrared applications because of its low phonon frequencies and other favorable features. In principle, Nd{sup 3+}:MPb{sub 2}Br{sub 5} has high potential for laser operation at new wavelengths as well as for the realization of short-wavelength lasing due to upconversion processes.