Multi-watt amplification in a birefringent Yb:LiLuF4 single crystal fiber grown by micro-pulling-down.

We present, to the best of our knowledge, the first demonstration of a single crystal fiber solid-state amplifier based on a birefringent Yb3+-doped thin crystal grown by the micro-pulling-down method. We measured a small signal gain >30 in a four-passes Yb:LiLuF4 amplifier pumping with a 120-W maximum power fiber-coupled laser diode. At an absorbed pump power of 80 W, a maximum output power of 8.4 W was obtained seeding the 42-mm-long, 2%Yb3+-doped single crystal fiber sample with 0.8 W at 1021 nm. Even at the maximum incident pump power, the amplified laser beam polarization and spatial quality were excellent (M2=1.15×1.06).

[1]  M. Tonelli,et al.  Laser investigation of Yb:YLF crystals fabricated with the micro-pulling-down technique. , 2018, Applied optics.

[2]  M. Tonelli,et al.  Crystal growth, spectroscopic characterization, and sub-100 femtosecond mode-locked operation of a Yb:LiLuF_4 laser , 2016 .

[3]  J. Zhang,et al.  Highly efficient waveguided laser performance of diode pumped unclad Yb:YAG crystalline fibre , 2016 .

[4]  Patrick Georges,et al.  High-power Yb:YAG single-crystal fiber amplifiers for femtosecond lasers in cylindrical polarization. , 2015, Optics letters.

[5]  Joachim Hein,et al.  Measurement of temperature-dependent absorption and emission spectra of Yb:YAG, Yb:LuAG, and Yb:CaF_2 between 20 °C and 200 °C and predictions on their influence on laser performance , 2012 .

[6]  Patrick Georges,et al.  250 W single-crystal fiber Yb:YAG laser. , 2012, Optics letters.

[7]  Yoann Zaouter,et al.  Direct amplification of ultrashort pulses in μ-pulling down Yb:YAG single crystal fibers , 2011, CLEO: 2011 - Laser Science to Photonic Applications.

[8]  O. Tillement,et al.  Diode-pumped laser with Yb:YAG single-crystal fiber grown by the micro-pulling down technique , 2009 .

[9]  Julien Didierjean,et al.  High-power laser with Nd:YAG single-crystal fiber grown by micro-pulling down technique , 2008, SPIE LASE.

[10]  T. Y. Fan,et al.  Measurement of thermo-optic properties of Y3Al5O12, Lu3Al5O12, YAIO3, LiYF4, LiLuF4, BaY2F8, KGd(WO4)2, and KY(WO4)2 laser crystals in the 80–300K temperature range , 2005 .

[11]  W. A. Clarkson,et al.  Thermal effects and their mitigation in end-pumped solid-state lasers , 2001 .