1.5-MHz repetition rate passively Q-switched Nd:YVO ₄ laser based on WS ₂ saturable absorber

Abstract

A transmission-type tungsten disulfide (WS 2 )-based saturable absorber (SA) is fabricated and applied to passively Q-switched Nd:YVO 4 laser. The WS 2 nanosheets are deposited on a quartz substrate by the vertical evaporation method. By inserting the WS 2 SA into the plano-concave laser cavity, we achieve 153-ns pulses with an average output power of 1.19 W at 1064 nm. To the best of our knowledge, both of them are the best results among those obtained by the Q-switched solid-state lasers with WS 2 -based absorbers. The repetition rate ranges from 1.176 MHz to 1.578 MHz. As far as we know, it is the first time that MHz level Q-switched pulses have been generated in all solid state lasers based on low-dimensional materials so far.

Synthesis of flower-like WS2 by chemical vapor deposition*

“…[1,2] WS 2 exhibits excellent optical, electrical and chemical sensing properties, making it promising for a wide range of applications like catalysis, laser modulation, batteries, and lubricants. [3][4][5] Such excellent properties of WS 2 are closely related to the number of layers and the geometrical morphology. As a result, the processing control over the synthesis of WS 2 materials to yield materials with better geometrical morphologies and good physical/chemical properties has attracted widespread attention.…”

Influences of annealing temperature on properties of Fe2+:ZnSe thin films deposited by electron beam evaporation and their applications to Q-switched fiber laser*

“…[1,11] Fe 2+ :ZnSe is not only a very excellent medium infrared laser material, but also an ideal passive saturable absorber. [12] Typical saturable absorbers such as two-dimensional (2D) materials, [13][14][15][16][17] Cr 4+ -doped crystals, [18,19] gold nanobipyramids (G-NBPs), [20] and Cr 2+ -doped chalcogenide crystals [21] have been widely studied. As a saturable absorber, the working wavelength range of the Fe 2+ :ZnSe laser is 2.5 µm-4.0 µm.…”

Passively Q-switched diode-pumped Tm, Ho:LuVO4 laser with a black phosphorus saturable absorber*

“…Recently, many two-dimensional (2D) materials such as graphene, [7] transition metal disulfides, [8][9][10][11] and topological insulators [12] were employed as the saturable absorber (SA) to achieve Q-switching thulium (Tm) or holmium (Ho)doped lasers at 2-µm. Compared with the above materials, black phosphorus (BP) with distinctive structure and properties [13,14] is an attractive and promising 2D material as a passive Q-switch SA.…”