High-Power Laser Performance of ${hbox {Yb:}}{hbox {YAl}}_{3}({hbox {BO}}_{3})_{4}$ Crystals Cut Along the Crystallographic Axes

摘要

High-power continuous-wave laser operation near 1 $mu{hbox {m}}$ was demonstrated at room temperature with ${mmb c}$-cut and ${mmb a}$-cut ${hbox {Yb:}}{hbox {YAl}}_{3}({hbox {BO}}_{3})_{4}$ crystals end-pumped by a fiber-coupled diode laser. Using a 2-mm-thick ${mmb c}$-cut crystal, 10.6 W of output power was generated with an optical-to-optical efficiency of 65% and a slope efficiency of 72%. The complex polarization state of the generated laser radiation was also studied. With a 2-mm-thick ${mmb a}$-cut crystal, $sigma$-polarized laser oscillation was obtained, producing a maximum output power of 8.1 W; the optical-to-optical and slope efficiencies were 56% and 61%, respectively. Complete absorption and emission cross section spectra of the ${hbox {Yb:}}{hbox {YAl}}_{3}({hbox {BO}}_{3})_{4}$ crystal were also derived, revealing very strong anisotropy of the spectroscopic properties.