Passive Q-switching of Yb bulk lasers by a graphene saturable absorber

Abstract

Abstract:We report efficient continuous-wave diode-pumped laser operation of Er,Yb:GdAl 3 (BO 3 ) 4 crystal. A maximal output power of 780 mW was obtained at 1531 nm at absorbed pump power of 4 W with slope efficiency of 26 %.

Graphene Q-switched Tm:KY(WO4)2waveguide laser

“…The output characteristics of the graphene-SA PQS Tm:KYW laser were modeled with a 'fast' SA model, see details in [19,22]. The parameters of the active material [7,11,12] and the SA [22] used for the calculations are summarized in table 1.…”

“…Graphene, a single layer of carbon atoms arranged in a honeycomb lattice, shows a broadband constant absorption of ~2.3%, ultrafast saturable absorption [17] characterized by low saturation intensity, good thermo-mechanical properties and reasonable laser damage threshold. Due to its special band structure, the graphene-SA is especially suitable for ~2 µm lasers because the saturation intensity at this wavelength (~0.6 MW cm −2 for ns-pulses) is lower than at ~1 µm [18,19] and, consequently, complete bleaching of the SA can be easily achieved.…”

Passively Q-Switched Operation of a Tm,Ho:LuVO4 Laser with a Graphene Saturable Absorber

“…A passively Q-switched (PQS) with a saturable absorber (SA) is a compact way, in which microsecond (µs) pulsed Q-switching operation in the mid-Mid-infrared wavelength range can be achieved. Recently, many SAs, such as carbon nanotubes, two-dimensional (2D) materials and ion-doped crystals, with broadband saturable absorption at 1-3 µm, have been used for passive Q-switching operations [5][6][7][8]. The carbon nanotubes are typically a one-dimensional (1D) SA material, which has been widely applied in fiber lasers emitting at wavelengths of 1-2 µm [5,9], but its performance is poor when used in solid-state lasers emitting at 2 µm, because its bandwidth is limited by the diameter of single-walled carbon nanotubes, and its broadband saturable absorption characteristics rely on mixing single-walled carbon nanotubes with different diameters [9].…”

Carbon nanotube Q-switched Yb:KLuW surface channel waveguide lasers

“…Based on a bulk crystal without WG structures, microchip lasers have been studied because of their low losses and insensitivity to alignment, enabling higher laser efficiency and output power. The Q-switched Yb-doped microchip lasers have been demonstrated using Cr:YAG, TMDs, and graphene placed between the microchip and the output coupler (OC) only based on direct-field coupling [15][16][17][18].…”

“…Subsequently, the experimental results are compared to the results from theoretical analyses. Note that the theoretical modeling of the Q-switching is based on the numerical solution of the rate equations for a quasi-three-level gain medium and a fast SA having fluence-dependent nonlinear absorption [14,16,25].…”