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Q-switched fiber laser based on CdS quantum dots as a saturable absorber
摘要： In this work, a Q-switched fiber laser is demonstrated using quantum dots (QDs) cadmium sulfide (CdS) as a saturable absorber (SA) in an erbium-doped fiber laser (EDFL) system. The QD CdS is synthesized via the microwave hydrothermal assisted method and embedded into polyvinyl alcohol (PVA). The QD CdS/PVA matrix film is sandwiched in between two fiber ferrules by a fiber adapter. The generation of Q-switched fiber laser having a repetition rate, a pulse width, and a peak-to-peak pulse duration of 75.19 kHz, 1.27 μs, and 13.32 μs, respectively. The maximum output power of 3.82 mW and maximum pulse energy of 50.8 nJ are obtained at the maximum pump power of 145.9 mW. The proposed design may add to the alternative material of Q-switched fiber laser generation, which gives a high stability output performance by using quantum dots material as a saturable absorber.
关键词： CdS Quantum Dots,erbium-doped fiber laser,microwave hydrothermal assisted method,saturable absorber,Q-switched fiber laser
更新于2025-09-23 15:19:57
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Zinc-oxide nanoparticle-based saturable absorber deposited by simple evaporation technique for Q-switched fiber laser
摘要： A Q-switched erbium-doped fiber laser (EDFL) incorporating zinc-oxide (ZnO) nanoparticles-based saturable absorber (SA) is proposed and demonstrated. To form the SA, the ZnO nanoparticles, which are originally in the powder form, are first dissolved in ethanol and subsequently deposited onto the surface of fiber ferrule by using the adhesion effect with the evaporation technique. By integrating the ZnO nanoparticle-based SA into a laser cavity of an EDFL, a self-started and stable Q-switching is achieved at a low threshold power of 20.24 mW. As the pump power is increased, the pulse repetition rate is tunable from 10.34 kHz to 25.59 kHz while pulse duration decreases from 21.39 μs to 3.65 μs. Additionally, this Q-switched laser has a maximum energy per pulse of 19.34 nJ and an average output power of 0.46 mW. These results indicate the feasibility and functionality of the ZnO nanoparticles-based SA for Q-switched generation, which offers the flexibility and easy integration of the SA into a ring laser cavity.
关键词： saturable absorber,zinc oxide,fiber laser,Q-switched
更新于2025-09-23 15:19:57
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Tunable indium tin oxide thin film as saturable absorber for generation of passively Q-switched pulse erbium-doped fiber laser
摘要： A tunable Q-switched pulse erbium-doped ?ber (EDF) laser using indium tin oxide (ITO) thin-?lm-based saturable absorber (SA) is proposed and demonstrated. The SA is formed by depositing an ITO layer using DC magnetron sputtering on the ?ber ferrule, which can be easily fabricated in less than 200 s with thickness of 17.80 nm. The proposed tunable Q-switched pulse EDF laser is operated from 1540.0 to 1570.0 nm, covering a total wavelength of 30.0 nm. The generated output pulses displayed a repetition rate range between 21.70 and 94.34 kHz. The shortest pulse width retrieved is 3.22 ls at the maximum pump power of 378.6 mW, while the maximum pulse energy recorded is 30.29 nJ. To the best of the authors’ knowledge, this appears to be the ?rst proposed tunable passively Q-switched pulse EDF laser using ITO that serves as SA, which can promote ITO ?lm in the application of ultrafast photonics.
关键词： DC magnetron sputtering,Saturable absorber,Indium tin oxide,Q-switching ?ber laser
更新于2025-09-23 15:19:57
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Passively Q-switched near-infrared lasers with bismuthene quantum dots as the saturable absorber
摘要： Bismuthene quantum dots (Bi-QDs) were synthesized via the liquid phase exfoliation (LPE) method for the passive Q-switching operation in near-infrared (NIR) region. The nonlinear optical properties of the prepared Bi-QDs were investigated by the open-aperture Z-scan technology. The modulation depths were 18.1% and 5.1% at 1.06 and 1.34 μm, respectively. Based on the Bi-QDs saturable absorber, passively Q-switched Nd:GdVO4 lasers operating at 4F3/2 → 2I11/2 and 4F3/2 → 2I13/2 transitions were demonstrated, showing the wideband optical modulation in NIR regime. For the 4F3/2 → 2I13/2 transition lasing at 1.34 μm, the shortest pulse duration of 155 ns was obtained with a repetition rate of 457 kHz. With respect to the 4F3/2 → 2I11/2 transition at 1.06 μm, the minimum pulse duration was 150 ns with a repetition rate of 424 kHz, leading to a single pulse energy of 261 nJ and a peak power of 1.68 W. In addition, the ground state absorption cross section and the excited state absorption cross section of Bi-QDs were also investigated for the ?rst time. The impact of the excited state lifetime on the output parameters was numerically stimulated by the coupled rate equations. Our work con-?rmed that the trap state in Bi-QDs played an important role in the pulse generation mechanism.
关键词： Saturable absorber,Bismuthene quantum dots,Q-switching,Nonlinear Optical properties,Rate equations
更新于2025-09-23 15:19:57
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Triplea??wavelength Qa??switched ytterbiuma??doped fiber laser based on tungsten oxide as saturable absorber
摘要： In this article, a multiwavelength Q-switched ytterbium-doped fiber laser using tungsten oxide nanoparticles (WO3 NPs) as a saturable absorber (SA) is reported for the first time. The SA was prepared by depositing micron-sized layers of WO3 NPs suspension onto the surface of the fiber tip via direct deposition process. After embedding the SA into an ytterbium-doped fiber laser cavity, self-starting Q-switched performance was realized at a bleaching threshold of 179 mW having a minimum pulse width of 2.92 μs and maximum pulse energy of 9.26 nJ with variable repetition rates from 14.8 to 71.3 kHz. By boosting the pump power and proper adjustment of the polarization controller, steady dual- and triple-wavelength operations were obtained at pump powers of 210 and 275 mW, respectively. The obtained results confirm the practical use of WO3 as an effective nonlinear modulator for multiwavelength and pulsed fiber lasers near 1 μm wavelength band.
关键词： multiwavelength,passive saturable absorber,YDFL,Q-switching,tungsten oxide nanoparticles
更新于2025-09-23 15:19:57
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Discovery of Several New Families of Saturable Absorbers for Ultrashort Pulsed Laser Systems
摘要： Saturable Absorber (SA) is a key element of any passive mode-locked laser system to provide ultrashort laser system. So far various materials have been proposed that could be used for this purpose. However, the field is still looking for new ways to make the fabrication process easier and cost-effective. Another challenge in testing mode-locked laser systems using various SA samples is the lack of knowledge in preparing these by laser physicists given this is outside their remit of expertise. In this study, we have proposed a novel method to produce these SAs from plastic materials and glycol. Our new method relies upon increase in thickness up to a value where the modulation depth is enough to give stable ultrashort pulses. Although we have shown this method for four materials; similar approach could be applied to any material. this will open the door of unlimited families of SAs that could be easily prepared and applied without any prior knowledge in material sciences.
关键词： Mode-locked laser,Glycol,Plastic materials,Saturable Absorber,Ultrashort pulsed Laser Systems
更新于2025-09-23 15:19:57
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MXene Ti3C2Tx saturable absorber for passively Q-switched mid-infrared laser operation of femtosecond-lasera??inscribed Er:Y2O3 ceramic channel waveguide
摘要： We report on an Er:Y2O3 ceramic channel waveguide laser operating at continuous-wave and passively Q-switched regimes, for the first time to the best of our knowledge. The Er:Y2O3 ceramic channel waveguide has been fabricated by a femtosecond laser direct-writing technique. The maximum output power reached 123.5 mW in continuous-wave mode with a slope efficiency of about 21%, and the lasing behavior has been found simultaneously at 2710.28, 2716.76, and 2723.18 nm. We have further fabricated an MXene Ti3C2Tx saturable absorber mirror to operate the Er:Y2O3 waveguide in passively Q-switched regime. At the same time, property of the MXene Ti3C2Tx saturable absorber has been characterized, and nonlinear saturable absorption of the saturable absorber has also been measured. The average output power is about 67.6 mW, and the shortest pulse width is about 58.1 ns. This work indicates that femtosecond laser direct writing is a reliable technique for processing mid-infrared ceramic waveguides, and MXene Ti3C2Tx is promising for operating pulsed mid-infrared lasers.
关键词： mid-infrared,MXene Ti3C2Tx saturable absorber,passive Q switching,waveguide
更新于2025-09-23 15:19:57
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Nonlinear Cyclotron Resonance Absorber for a Microwave Subnanosecond Pulse Generator Powered by a Helical-Waveguide Gyrotron Traveling-Wave Tube
摘要： A well-known principle for periodical production of high-power ultrashort optical pulses is related to passive mode locking realized when a saturable absorber is incorporated into the laser resonator. A similar effect can be implemented in two-section electronic oscillators comprising an amplifier and a saturable absorber, which should be applicable in the microwave frequency band and suitable for high-power operation. In this paper, we analyze in detail the possibility of realizing a saturable absorber based on cyclotron resonance interaction in the regular waveguide with initially rectilinear electron beam, when saturation is caused by the relativistic dependence of the gyrofrequency on electron energy. Maximum contrast between the absorption of a high-power signal and of a weak signal is achieved in the group synchronism regime when the particle velocity is close to the wave’s group velocity. Within the frame of a time-domain self-consistent model, we demonstrate that when such an absorber is installed in the feedback loop of an electron generator powered by existing Ka-band helical-waveguide gyrotron traveling-wave tube, periodical generation of subnanosecond pulses can be provided with peak power up to several hundred kW and sub-GHz repetition frequency. We discuss the influence of deviation from the group synchronism regime on the parameters of generated pulses. Experimental feasibility of the considered scheme is verified based on three-dimensional particle-in-cell simulations.
关键词： gyrotron traveling-wave tube,cyclotron resonance,subnanosecond pulse,saturable absorber,microwave
更新于2025-09-23 15:19:57
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Semiconducting Polymer Dots as Broadband Saturable Absorbers for Q-switched Fiber Lasers
摘要： Semiconducting polymer dots (Pdots) have attracted much attention due to their outstanding optical properties. However, Pdots potential in laser technology is rare. Here, we first report the benzobisthiadiazole (BBT)-based Pdot as a single broadband nonlinear saturable absorber (SA) for passively Q-switched fiber lasers at 1, 1.5, and 2 μm. The Pdots-SA possesses a strong saturable absorption, broadband nonlinear optical response, and large modulation depth. Once the Pdots-SA is integrated into the ytterbium-, erbium-, and thulium-doped fiber laser cavities, stable Q-switched operations are observed at the central wavelengths of 1036, 1561, and 1951 nm. Our results verify that the Pdots are promising nonlinear media for Q-switched pulses generation, and highlight the potential of Pdots for relevant nonlinear optical applications.
关键词： Saturable absorber,Semiconducting polymer dots,Q-switched fiber lasers,Broadband nonlinear optical response
更新于2025-09-23 15:19:57
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Tungsten tri-oxide (WO <sub/>3</sub> ) film absorber for generating Q-switched pulses in erbium laser
摘要： This paper reports a new type of passive saturable absorber (SA) made of transition metal oxide (TMO) embedded in polyvinyl alcohol (PVA). The Tungsten trioxide (WO3)-PVA SA is placed in an erbium-doped fibre laser cavity to produce Q-switched pulses operating at 1562.82 nm. The pulse laser starts to manifest at the threshold pump power of 40 mW and continues to exist until the maximum pump power of 195 mW. Within that pump power range, its pulse energy, repetition rate and pulse width vary from 98 to 142.85 nJ, 29.86 to 56.7 kHz and 5.032 to 1.85 μs, respectively. The pulse train is stable with a signal to noise ratio of 70 dB. This is the first demonstration of a Q-switched laser using such a SA.
关键词： saturable absorber,WO3,Q-switched,Erbium-doped fibre laser
更新于2025-09-23 15:19:57