Highly efficient passivelyQ-switched Tm,Ho:GdVO₄laser with kilowatt peak power

Abstract

We present the experimental results on the laser characteristics of diode-pumped passively Q-switched Tm,Ho:GdVO 4 and Tm,Ho:YVO 4 lasers with a Cr 2þ ∶ZnS saturable absorber emitting in the 2-μm range. The Tm,Ho:GdVO 4 laser exhibits better performance than the Tm,Ho:YVO 4 laser. The minimum pulse duration of 32.7 ns is obtained with the pulse energy of 0.30 mJ, corresponding to the peak power of 9.1 kW. The slope efficiencies of continuous wave and passively Q-switched Tm,Ho:GdVO 4 lasers are 49.9% and 36.5%, corresponding to the Q-switching efficiency of 70.2%.

Experimental Investigation of Double-End Pumped Tm, Ho: GdVO4 Laser at Cryogenic Temperature

“…At cryogenic temperature, we also had demonstrated PQS Tm, Ho-codoped vanadate lasers with Cr:ZnS SA [21,22]. The highest peak power of ~9.1 kW was achieved with the pulse duration of 32.7 ns [23]. In this paper, to improve the peak power, the comparative research for the PQS lasers with different pump mode radius was experimentally conducted.…”

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].…”

“…2D materials are low-cost materials offering excellent performance and are used as the SA for PQS and mode-locked mode operations, due to their ultrafast recovery time, moderate modulation depth, high nonlinear effects and broadband saturable absorption [10,11]. Compared with the 1D and 2D SAs, ion-doped crystals, such as the Cr:ZnS crystal, have inherent defects which affect the stability, electronic structures and optical properties of ion-doped crystals [8,12].…”

“…Vanadate crystals are of particular interest as a potential laser host material, because they are suitable for rare-earth ions doped or co-doped lasers, such as Nd:GdVO 4 , Nd:GdVO 4 , Tm,Ho:YVO 4 , Tm,Ho:GdVO 4 , Ho:LVO 4 and Tm,Ho:LuVO 4 [8,[19][20][21][22][23][24][25]. Nd:GdVO 4 and Nd:YVO 4 lasers have been demonstrated at 1 µm wavelength range [26,27].…”

“…Nd:GdVO 4 and Nd:YVO 4 lasers have been demonstrated at 1 µm wavelength range [26,27]. Tm,Ho:YVO 4 and Tm,Ho:GdVO 4 have been used as the laser crystal in continuous wave (CW), PQS, and acousto-optically (AO) Q-switched mode operation, and PQS Tm,Ho:YVO 4 and Tm,Ho:GdVO 4 laser were demonstrated with an SA of a 2 mm-thick Cr:ZnS crystal with a pulse width of less than 100 ns and a pulse energy over 100 µJ [8,28]. However, 2D materials were rarely used as an SA for Tm 3+ and Ho 3+ co-doped vanadate crystals in PQS laser operations.…”