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Laser excitation dependent nonlinear absorption of 2-Amino 5-Nitropyridinium dihydrogen phosphate
摘要： Laser excitation and intensity-dependent third-order nonlinear (NLO) absorption properties of 2-amino 5-nitropyridinium dihydrogen phosphate (2A5NPDP) in both pulsed (532 nm, 5 ns, 100 mJ) and continuous wave (532 nm, 50 mW) regime were studied by Z-scan experiment. Under CW laser excitation, 2A5NPDP exhibits saturable absorption (SA) ascribed to be of thermo-optic origin. Interestingly the sample show reverse saturable absorption (RSA) due to genuine two-photon absorption (2PA) process under nano pulsed laser excitation. Earlier thermodynamic properties such as thermal conductivity (51 W/m.K), specific heat capacity (3894 J/Kg.K) and thermal diffusivity (7.5 (cid:1) 10(cid:3)6 m2/s) were estimated theoretically from the DSC curves. Thus 2A5NPDP with excellent thermal stability and high NLO coefficients can be utilized as an energy-absorbing optical limiter and saturable absorber under nano pulsed and CW green laser excitation.
关键词： Genuine 2PA,semiorganic NLO,saturable absorber,optical limiter
更新于2025-09-23 15:19:57
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Threshold decrease and output-power improvement in dual-loss Q-switched laser based on few-layer WTe<sub>2</sub> saturable absorber
摘要： A dual-loss Q-switched laser was realized by applying a home-made 2.5 nm-thick WTe2 to an acoustic-optic (AO) modulated laser. Besides conventional pulse compression, the participation of WTe2 could obviously improve the average output power by 29.6% and reduce the laser threshold by 20%, even with the introduced 8% nonsaturable loss. The average-output-power improvement and pulse compression in this dual-loss modulated laser resulted in a 113.7% increase of peak power. According to the measured spectra of laser and photoluminescence of WTe2, the laser-induced excitonic light-emission may be the reason of this laser gain.
关键词： WTe2 saturable absorber,laser threshold decrease,pulse compression,output-power improvement,dual-loss Q-switched laser
更新于2025-09-23 15:19:57
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Promotion impact of thermal oxidation etching to saturable absorption performance of g-C3N4
摘要： A facile thermal modification method based on thermal oxidation etching was successfully developed as an effective way of improving the photoelectric properties of graphite carbon nitride (g-C3N4), and the as-prepared modified g-C3N4 was employed as the saturable absorber (SA) for a passively Q-switched Nd:LLF laser at 1.06 μm to improve the laser performance. Under the incident pump power of 7.68 W, a pulsed laser output with 110 ns pulse width at 95.5 kHz pulse repetition rate was achieved, which was the narrowest among the g-C3N4 materials used as SAs around 1 μm.
关键词： Q-switched laser,2D materials,g-C3N4 saturable absorber,Infrared lasers
更新于2025-09-19 17:15:36
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MAX phase based saturable absorber for mode-locked erbium-doped fiber laser
摘要： We presented an ultrashort pulse generation in an erbium-doped fiber laser cavity using MAX-PVA as a mode-locker. A thin film of SA was prepared by mixing PVA with Ti3AlC2 as a saturable absorber inside the laser cavity. The optical nonlinearity was also demonstrated, revealing a saturable absorption of 2%, a non-saturable absorption of 58.2%, and a saturation intensity of 1.63 MW/cm2. The excellencies of MAX-PVA was proven as it initiates ultrafast laser with a duration of 3.68 ps corresponds to a repetition rate of 1.887 MHz. The ease of preparation, together with its superior optical, physical, thermal, and mechanical properties, makes it a favorable SA for pulse generation in an all-fiberized laser cavity.
关键词： Ultrashort pulse,MAX phase,Erbium-doped fiber laser,Saturable absorber,Mode-locked
更新于2025-09-19 17:13:59
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Recent progress in ultrafast lasers based on 2D materials as a saturable absorber
摘要： Two-dimensional (2D) materials are crystals with one to a few layers of atoms and are being used in many fields such as optical modulator, photodetector, optical switch, and ultrafast lasers. Their exceptional optoelectronic and nonlinear optical properties make them as a suitable saturable absorber for laser cavities. This review focuses on the recent progress in ultrafast laser use 2D materials as a saturable absorber. 2D materials traditionally include graphene, topological insulators, transition metal dichalcogenides, as well as new materials such as black phosphorus, bismuthene, antimonene, and MXene. Material characteristics, fabrication techniques, and nonlinear properties are also introduced. Finally, future perspectives of ultrafast lasers based on 2D materials are also addressed.
关键词： saturable absorber,MXene,antimonene,bismuthene,graphene,ultrafast lasers,transition metal dichalcogenides,black phosphorus,2D materials,topological insulators
更新于2025-09-19 17:13:59
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Output energy enhancement in a dual-wavelength Q-switched fiber laser based on a ternary MoWSe2 saturable absorber
摘要： As a novel ternary selenide-based transition metal dichalcogenide (TMD), few-layered molybdenum tungsten selenide (MoWSe2) was fabricated using liquid phase exfoliation method and applied in a Q-switched fiber laser as a saturable absorber. Dual-wavelength operation was achieved with the increase of pumping strength. The shortest pulse width and the maximum repetition rate were monitored to be 1.53 μs and 85.71 kHz, corresponding to a maximum single pulse energy and peak power of 151.4 nJ and 98.91 mW, respectively. The results indicate ternary MoWSe2 could be a promising candidate in Q-switched laser applications.
关键词： Saturable absorber,MoWSe2 nano-materials,Q-switched fiber laser
更新于2025-09-19 17:13:59
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Switchable and dual-wavelength ultrafast fibre lasers with an MoTe <sub/>2</sub> -based saturable absorber
摘要： Based on monolayer MoTe2 film, we have proposed a mode-locked fibre laser delivering single-wavelength and dual-wavelength solitons at the telecommunication band. The saturable absorber (SA) is synthesized by coating monolayer MoTe2 film on the pinhole of fibre pigtail. The experimental results show that our soliton lasers can work at the single- and dual-wavelength states, respectively, by appropriately adjusting the polarization controller. The proposed laser can work stably at the mode-locking state for several hours, indicating that monolayer MoTe2 film is an excellent SA material for ultrafast optics.
关键词： ultrafast fibre laser,two dimensional materials,Saturable absorber
更新于2025-09-19 17:13:59
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Polarization domain wall solitons in a quasi-isotropic fibre laser using quantum dot tungsten disulfide
摘要： A passively fast polarization switching erbium-doped fibre laser using quantum dot tungsten disulfide (QDWS2) as a saturable absorber (SA) has been proposed. It could generate polarization domain walls (PDWs). The PDWs’ spectrum can be divided into two separated spectra, which are orthogonally polarized. In detail, the horizontal polarization component wavelength is centred at 1561.1 nm with a repetition rate of 19.347 MHz, a pulse duration of 30 ns, and a signal-to-noise ratio of 73.2 dB at the maximum pump power. The vertical polarization component wavelength is centred at 1561.5 nm, with a pulse duration of 20.4 ns. To the best of our knowledge, this is the first report of a polarization domain wall generated by a QDWS2-SA. These results provide a platform to investigate anticorrelated polarization dynamics in quasi-isotropic fibre lasers. Moreover, their robustness and attractive properties could find potential applications in optical communications, data storage, and fibre laser devices.
关键词： saturable absorber,polarization domain wall soliton,fibre laser
更新于2025-09-19 17:13:59
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Improved Phase Locking of Laser Arrays with Nonlinear Coupling
摘要： An arrangement based on a degenerate cavity laser for forming an array of nonlinearly coupled lasers with an intracavity saturable absorber is presented. More than 30 lasers were spatially phase locked and temporally Q switched. The arrangement with nonlinear coupling was found to be 25 times more sensitive to loss differences and converged five times faster to the lowest loss phase locked state than with linear coupling, thus providing a unique solution to problems that have several near-degenerate solutions.
关键词： saturable absorber,laser arrays,degenerate cavity laser,nonlinear coupling,Phase locking
更新于2025-09-19 17:13:59
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Niobium disulfide as a new saturable absorber for an ultrafast fiber laser
摘要： Group VB transition metal dichalcogenides (TMDCs) are emerging two-dimensional materials and have attracted significant interests in the fields of physics, chemistry, and material sciences. However, there are very few reports about the optical characteristics and ultrafast photonic applications based on group VB TMDCs so far. In this work, we have calculated the niobium disulfide (NbS2) band structure by the density functional theory (DFT), which has revealed that NbS2 is a metallic TMDC. In addition, we have prepared an NbS2-microfiber device and the nonlinear optical characteristics have been investigated. The modulation depth, saturation intensity and non-saturable loss have been measured to be 13.7%, 59.93 MW cm?2 and 17.74%, respectively. Based on the nonlinear optical modulation effect, the Er-doped fiber (EDF) laser works in the soliton mode-locking state with the pump power of 94–413 mW. The pulse duration of 709 fs and the maximum average output power of 23.34 mW have been obtained at the pump power of 413 mW. The slope efficiency is as high as 6.79%. Compared to the recently reported studies based on TMDCs comprehensively, our experimental results are better. These experimental results demonstrate that NbS2 with excellent nonlinear optical properties can be used as a promising candidate to advance the development of ultrafast photonics.
关键词： Niobium disulfide,ultrafast fiber laser,saturable absorber,mode-locking,nonlinear optical properties
更新于2025-09-19 17:13:59