Passively Q-Switched Tm,Ho:YVO₄Laser with Cr:ZnS Saturable Absorber at 2 μm

Abstract

A stable diode-pumped passively Q-switched Tm,Ho:YVO4 laser with Cr:ZnS saturable absorber is reported. The shortest pulse duration of ∼500 ns with the central wavelength of 2041 nm is obtained at the pump power of 7.4 W, corresponding to the pulse energy of 3.5 𝜇J at repetition rate of 65 kHz.

Passive Q-switching of a Tm,Ho:KLu(WO_4)_2 microchip laser by a Cr:ZnS saturable absorber

“…With higher modulation depth of the SA (α 0 SA 3.5%), a pulse duration of 9 ns was achieved, the shortest ever reported for a PQS Tm,Ho-doped laser. At a pulse energy of 10.4 μJ, this corresponds to a record peak power of 1.15 kW, the highest ever extracted from a room-temperature PQS Tm,Ho laser, exceeding >50 times the previous results [19][20][21][22][23]. A theoretical model of a quasi-three-level laser system PQS with a "slow" SA is developed.…”

“…Passive Q-switched laser operation at room temperature is more favorable to benefit from the compactness of the cavity. A comparison of passively Q-switched Tm,Ho bulk lasers reported so far [19][20][21][22][23] is presented in Table 2. Two types of SAs were employed in these lasers, namely, Cr:ZnS and carbon nanostructures (graphene and single-walled carbon nanotubes, SWCNTs).…”

“…We are aware of only one report on a PQS Tm,Ho microchip laser [19]. However, due to one particular limitation of the SA used in [19] (single-layer graphene), namely, the low modulation depth, this laser generated 200 ns∕ 0.2 μJ pulses with a peak power of only ∼1 W. Several previous studies were devoted to PQS Tm,Ho bulk lasers using LiYF 4 , LiLuF 4 , YAlO 3 , and YVO 4 host crystals and Cr 2 :ZnS or carbon nanostructures as SAs [20][21][22][23]. However, in such lasers, the typical pulse durations were still a few hundred nanoseconds (ns) and the peak power did not exceed a few tens of watts (W).…”

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

“…Based on Cr 2+ :ZnS SA, Tm, Ho-codoped laser with different hosts such as LLF [18], YLF [19], and KLu (WO 4 ) 2 [20] have been presented. 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].…”

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

“…In addition, at low temperature, due to excellent thermo-optic properties and spectroscopic properties of the laser crystals, 16 the lasers can generate high output power and efficiency. 20 The pulse duration of the Tm,Ho codoped vanadate lasers kept being several hundred nanoseconds, with the pulse repetition rate of tens of thousands of Hertz and low efficiencies, which drastically limited the pulse energy and peak power to less than 1 kW. 17,18 Using Cr:ZnS as SA, we have demonstrated a cryogenic PQS double-crystal Tm,Ho:GdVO 4 laser with the maximum pulse energy of 70.5 μJ.…”