Thermal Characterization, Crystal Field Analysis and In-Band Pumped Laser Performance of Er Doped NaY(WO4)2 Disordered Laser Crystals. e59381

• Published in: PloS one Vol. 8; no. 3
• Main Authors: Serrano, Maria Dolores, Cascales, Concepcion, Han, Xiumei, Zaldo, Carlos, Jezowski, Andrzej, Stachowiak, Piotr, Ter-Gabrielyan, Nikolay, Fromzel, Viktor, Dubinskii, Mark
• Format: Journal Article
• Language: English
• Published: 01-03-2013
• Subjects: Absorption
• ISSN: 1932-6203
• DOI: 10.1371/journal.pone.0059381

Undoped and Er-doped NaY(WO4)2 disordered single crystals have been grown by the Czochralski technique. The specific heat and thermal conductivity ( Kappa ) of these crystals have been characterized from T = 4 K to 700 K and 360 K, respectively. It is shown that Kappa exhibits anisotropy characteristic of single crystals as well as a Kappa (T) behavior observed in glasses, with a saturation mean free phonon path of 3.6 Aa and 4.5 Aa for propagation along a and c crystal axes, respectively. The relative energy positions and irreducible representations of Stark Er3+ levels up to 4G7/2 multiplet have been determined by the combination of experimental low (<10 K) temperature optical absorption and photoluminescence measurements and simulations with a single-electron Hamiltonian including both free-ion and crystal field interactions. Absorption, emission and gain cross sections of the 4I13/2 reversible reaction 4I15/2 laser related transition have been determined at 77 K. The 4I13/2 Er3+ lifetime ( tau ) was measured in the temperature range of 77-300 K, and was found to change from tau (77K) approximately 4.5 ms to tau (300K) approximately 3.5 ms. Laser operation is demonstrated at 77 K and 300 K by resonantly pumping the 4I13/2 multiplet at lambda approximately 1500 nm with a broadband (FWHM approximately 20 nm) diode laser source perfectly matching the 77 K crystal 4I15/2 arrow right 4I13/2 absorption profile. At 77 K as much as 5.5 W of output power were obtained in pi -polarized configuration with a slope efficiency versus absorbed pump power of 57%, the free running laser wavelength in air was lambda approximately 1611 nm with the laser output bandwidth of 3.5 nm. The laser emission was tunable over 30.7 nm, from 1590.7 nm to 1621.4 nm, for the same pi -polarized configuration.