Enhanced performance of acousto-opticQ-switched Er:Yb:RAl₃(BO₃)₄(R = Y and Lu) pulse lasers at 1580 nm

Abstract

By using mirrors with specially designed transmissions in a diode end-pumped hemispherical cavity, laser oscillations except for 1580 nm were suppressed and an enhanced pulse performance of an acousto-optic Q-switched laser at a single wavelength of 1580 nm was realized for Er:Yb:RAl 3 (BO 3 ) 4 crystals. When the absorbed pump power was 13.5 W and the pulse repetition frequency was 1 kHz, 250 µJ Q-switched pulse energy with a width of 215 ns and 350 µJ Q-switched pulse energy with a width of 125 ns were achieved in Er:Yb:YAl 3 (BO 3 ) 4 and Er:Yb:LuAl 3 (BO 3 ) 4 crystals, respectively. The pulsed laser performances of both the crystals were also compared and investigated in detail.

Crystal structures and comparisons of huntite aluminum borates REAl3(BO3)4 (RE = Tb, Dy and Ho)

“…Rare-earth aluminum borates (REAB) with the general chemical formula REAl 3 (BO 3 ) 4 (RE = La, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y) have been studied extensively for applications in lasers, nonlinear optics, sensors, and phosphors because of their optical and magnetoelectric properties as well as the capacity to be doped with other rare-earth metals (Koporulina et al, 2000;Leonyuk & Leonyuk, 1995;Leonyuk et al, 1998;Mills, 1962;Belokoneva & Timchenko, 1983;Belokoneva, 1994). The REAB crystals are promising materials for self-frequency-doubling lasers as their nonlinear optical properties can be changed by doping with different rare-earth elements including Nd, Dy, Er, Yb, Tm, or Y (Leonyuk et al, 1998(Leonyuk et al, , 2007Fö ldvá ri et al, 2003;Chen et al, 2012). The REAB compounds with RE = Tb, Ho, Er, or Tm exhibit the magnetoelectric properties useful for sensor applications (Liang et al, 2011(Liang et al, , 2012, and REAB with the RE = Pr, Sm, Eu, Gd, Tb, or Ho can be used as phosphors (Li & Wang, 2007;He et al, 2015).…”

Structure and nonlinear optical properties of novel transparent glass-ceramics based on Co2+:ZnO nanocrystals

“…In the visible part of the spectrum, there is a gradual reduction of absorption at ~525 nm, an appearance of a shoulder at ~565 nm, a shift of the absorption bands at 590 and 640 nm to 607 and 643 nm, respectively, and an increase The absorption bands observed for GCs coincide well with the ones for Co 2+ :ZnO [30,31] and they can be ascribed to the d-d transitions of Co 2+ ions with 3d 7 high-spin configuration in a tetrahedral ligand field formed by neighboring oxygen ions in ZnO nanocrystals. Three absorption peaks in the visible range are assigned as 4 A 2 (F) → 2 E(G), 4 A 2 (F) → 4 T 1 (P), and 4 A 2 (F) → 2 A 1 (G) transitions. The absorption band in the infrared is associated with the electronic transitions from the 4 A 2 (F) ground-state to the 4 T 1 (F) excited multiplet.…”

“…Three absorption peaks in the visible range are assigned as 4 A 2 (F) → 2 E(G), 4 A 2 (F) → 4 T 1 (P), and 4 A 2 (F) → 2 A 1 (G) transitions. The absorption band in the infrared is associated with the electronic transitions from the 4 A 2 (F) ground-state to the 4 T 1 (F) excited multiplet. This is actually the band intended to be used for Q-switching of erbium lasers.…”

“…State-of-the-art materials for (Er 3+ ,Yb 3+ ) codoping are phosphate glasses providing very high efficiencies of the ET but possessing very poor thermal properties [1]. Thus, several crystalline materials were proposed as an alternative for the glass in terms of thermo-mechanical properties, however, only a few of them, basically borates such as REAl 3 (BO 3 ) 4 where RE = Y, Gd or Lu [2][3][4] can compete with phosphate glasses in terms of ET efficiency. In addition, they provide low thermo-optic aberrations [5].…”

“…Phosphate glass [6,7] and crystalline borate [8] lasers can be efficiently Q-switched by Co:MgAl 2 O 4 spinel single crystals using the saturable absorption related to the 4 A 2 ( 4 F) → 4 T 1 ( 4 F) transition of tetrahedrally coordinated…”