β-Ga2O3 Used as a Saturable Sbsorber to Realize Passively Q-Switched Laser Output

β-Ga2O3 crystals have attracted great attention in the fields of photonics and photoelectronics because of their ultrawide band gap and high thermal conductivity. Here, a pure β-Ga2O3 crystal was successfully grown by the optical floating zone (OFZ) method, and was used as a saturable absorber to realize a passively Q-switched all-solid-state 1 μm laser for the first time. By placing the as-grown β-Ga2O3 crystal into the resonator of the Nd:GYAP solid-state laser, Q-switched pulses at the center wavelength of 1080.4 nm are generated under a output coupling of 10%. The maximum output power is 191.5 mW, while the shortest pulse width is 606.54 ns, and the maximum repetition frequency is 344.06 kHz. The maximum pulse energy and peak power are 0.567 μJ and 0.93 W, respectively. Our experimental results show that the β-Ga2O3 crystal has great potential in the development of an all-solid-state 1 μm pulsed laser.

β-Ga2O3 Used as a Saturable Absorber to Realize Passively Q-Switched Laser Output

β-Ga2O3 crystal have attracted great attentions in the fields of photonics and photoelectronics because of its ultra wide-band gap and high thermal conductivity. Here, pure β-Ga2O3 crystal was successfully grown by optical floating zone (OFZ) method, and used as saturable absorbers to realize a passively Q-switched all-solid-state 1μm laser for the first time. By placing the as-grown β-Ga2O3 crystal into the resonator of Nd:GYAP solid-state laser, a Q-switched pulses at the center wavelength of 1080.4 nm are generated under a output coupling of 10%. The maximum output power is 191.5 mW while the shortest pulse width is 606.54 ns, and the maximum repetition frequency is 344.06 kHz. The maximum pulse energy and peak power are 0.567 μJ and 0.93 W, respectively. Our experimental results show that β-Ga2O3 crystal has great potential in the development of all-solid-state 1μm pulsed laser.

Q-switched Ytterbium-doped fibre laser using an 8 cm long Hafnium bismuth erbium co-doped fibre saturable absorber

In this paper, we present a Q-switched fibre laser at 1069 nm which is induced by an 8 cm long Hafnium bismuth erbium co-doped fibre (HBEDF) saturable absorber (SA). The pulsating laser has a maximum repetition rate of 67 kHz at 175 mW pump power. We obtained the narrowest pulse width of 3.48 μs, the maximum pulse energy of 70.2 nJ, the maximum output power of 4.7 mW and the maximum peak power of 20.1 mW. The Q-switched laser is simple and may found practical applications in medicine and remote sensing.

Metallic 2H-Tantalum Selenide Nanomaterials as Saturable Absorber for Dual-Wavelength Q-Switched Fiber Laser

A novel 2H-phase transition metal dichalcogenide (TMD)–tantalum selenide (TaSe2) with metallic bandgap structure is a potential photoelectric material. A band structure simulation of TaSe2 via ab initio method indicated its metallic property. An effective multilayered TaSe2 saturable absorber (SA) was fabricated using liquid-phase exfoliation and optically driven deposition. The prepared 2H–TaSe2 SA was successfully used for a dual-wavelength Q-switched fiber laser with the minimum pulse width of 2.95 μs and the maximum peak power of 64 W. The repetition rate of the maximum pulse energy of 89.9 kHz was at the level of 188.9 nJ. The metallic 2H–TaSe2 with satisfactory saturable absorbing capability is a promising candidate for pulsed laser applications.

Titanium Disulfide Based Saturable Absorber for Generating Passively Mode-Locked and Q-Switched Ultra-Fast Fiber Lasers

In our work, passively mode-locked and Q-switched Er-doped fiber lasers (EDFLs) based on titanium disulfide (TiS2) as a saturable absorber (SA) were generated successfully. Stable mode-locked pulses centred at 1531.69 nm with the minimum pulse width of 2.36 ps were obtained. By reducing the length of the laser cavity and optimizing the cavity loss, Q-switched operation with a maximum pulse energy of 67.2 nJ and a minimum pulse duration of 2.34 µs was also obtained. Its repetition rate monotonically increased from 13.17 kHz to 48.45 kHz with about a 35 kHz tuning range. Our experiment results fully indicate that TiS2 exhibits excellent nonlinear absorption performance and significant potential in acting as ultra-fast photonics devices.

Graphene slurry based passive Q-switcher in erbium doped fiber laser

In this work, a Graphene slurry based passive Q-switcher fabricated from Graphene-Polylactic acid (PLA) filament which is used for 3D printing. To produce the Graphene slurry, the diameter of the filament was reduced and Tetrahydrofuran (THF) was used to dissolve the PLA. The Graphene-THF suspension was drop cast to the end of a fiber ferrule and the THF then evaporated to develop Graphene slurry based SA which is integrated in fiber laser cavity. At threshold input pump power of 30.45 mW, a Q-switched Erbium-doped fiber laser (EDFL) can be observed with the wavelength centered at 1531.01 nm and this remained stable up to a pump power of 179.5 mW. As the pump power was increased gradually, an increase in the repetition rates was recorded from 42 kHz to 125 kHz, while the pulse width was reduced to 2.58 μs from 6.74 μs. The Q-switched laser yielded a maximum pulse energy and peak power of 11.68 nJ and 4.16 mW, respectively. The proposed Graphene slurry based saturable absorber also produced a signal-to-noise ratio of 44 dB indicating a stable Q-switched pulsed laser.

Graphite Saturable Absorber for Q-Switched Fiber Laser

This paper reported a successful demonstration on Q-switched fiber laser by using graphite as saturable absorber (SA). The graphite is deposited on the fiber ferrule through a simple mechanical exfoliation method. The modulation depth of the graphite SA is 19.2% with a saturation intensity of 85 MW/cm². The maximum achievable pulse repetition rates and pulse width are 42.41 kHz and 3.40 μs respectively. Meanwhile, its optical signal-to-noise ratio is about 50.81 dB. The Q-switched pulses have the maximum pulse energy of 5.84 nJ. These outcomes demonstrated that a stable output of passively Q-switched fiber laser is produced and can be applied for various optical fiber applications.

Experimental and Numerical Comparison Q-Switched Fiber Laser Generation using Graphene as Saturable Absorber

We demonstrated the comparison experimentally and numerically a compact Q-switched erbium-doped fiber (EDF) laser based on graphene as a saturable absorber (SA). By optically driven deposition of graphene on a fiber core, the SA is constructed and inserted into a diode-pumped EDF laser cavity. Lasing in CW region starts at 10 mW, whereas stable self-starting Q-switching with a central wavelength of 1530 nm begins at 18 mW. In this paper, at 35 mW, the maximum pulse energy reaches at 2 μJ with pulse repetition rate of 1 MHz and the narrowest pulse width is around 10 μs is obtained. The stability of the pulse is verified from the radio-frequency (RF) spectrum with a measured signal-to-noise ratio (SNR) of 48 dB. In this study, the design is compared with the simulation using the Optisystem software. The output power of the experimental study is also compared with the simulation to examine the performance.

Static and dynamic characterization of biomedical polyethylene laser welding using biocompatible nano-particles

In this research, polymeric joints of Ultra High Molecular Weight Polyethylene (UHMWPE) sheets were realized and welded by a diode laser operating at 970 nm wavelength. One of the polymer sheet was doped, at different concentrations, with nano filler (carbon, titanium and silver nano-particles) in order to enhance the absorption coefficient at the laser wavelength. Laser operated in repetition rate with a maximum pulse energy 100 mJ, for times of the order of 1-60 s transporting the light trough a fiber with 300 μm diameter. The laser light has been transmitted by the transparent first polymer and absorbed on the face of the second doped polymer. At the interface of the two polymer foils, 0.5 mm thickness each, the released energy induces melting, assisted by pressure, producing a fast and resistant welding. Single lap and double lap geometries have been performed and studied by means of mechanical static (shear stress) and dynamical analysis. Effect of the different particles nature on the mechanical features of the joints has been evaluated. Morphological observation of the jointed areas are presented and discussed. Joints could be useful in biomedical field for their special features.

Black Phosphorus Q-Switched Large-Mode-Area Tm-Doped Fiber Laser

We report on a passively Q-switched fiber laser with black phosphorus as saturable absorber. By employing the sol-gel fabricated large-mode-area Tm-doped fiber as gain medium, a high-energy Q-switched fiber laser has been demonstrated which delivers the maximum pulse energy of 11.72 μJ with the pulse width of 660 ns at the wavelength of 1954 nm. Our experimental results indicate that BP Q-switched large-mode-area Tm-doped fiber laser is an effective and reliable approach to generate high-energy pulses at 2 μm.