Random laser emission from neodymium doped alumina lead-germanate glass powder

Random lasing is reported for the first time, to our knowledge, in neodymium doped alumina lead-germanate (GPA) glass powder. The samples were fabricated by a conventional melt-quenching technique at room temperature, and x-ray diffraction was used to confirm the amorphous structure of the glass. Powders with average grain size of about 2 mu m were prepared by grinding the glass samples and using sedimentation in isopropyl alcohol to remove the coarsest particles. The sample was excited using an optical parametric oscillator tuned to 808 nm, in resonance with the neodymium ion (Nd3+) transition 4I9/2 -> {4F5/2, 2H9/2}. Random laser (RL) emission at 1060 nm (Nd3+ transition: 4F3/2 -> 4I11/2) was observed for an energy fluence excitation threshold (EFErmth) of about 0.3 mJ/mm2. Above the EFEth, a short RL pulse in the nanosecond range is observed, corroborating the lasing process. Contrary to what one might suppose, the use of large quantities of neodymium oxide (10% wt. of Nd2O3) in the GPA glass, which leads to luminescence concentration quenching (LCQ), is not a disadvantage, once stimulated emissions (RL emission) occur faster than the nonradiative energy-transfer time among Nd3+ ions responsible for the LCQ.(c) 2023 Optica Publishing Group

Automated summary

Random lasing is observed in neodymium doped alumina lead-germanate glass powder for the first time. The samples were fabricated using a conventional melt-quenching technique and confirmed to have an amorphous structure. Excitation of the sample at 808 nm resulted in random laser emission at 1060 nm, with an excitation energy fluence threshold of 0.3 mJ/mm2. The use of large quantities of neodymium oxide in the glass did not hinder the laser emission process, despite luminescence concentration quenching.