High-Quality, InN-Based, Saturable Absorbers for Ultrafast Laser Development

New fabrication methods are strongly demanded for the development of thin-film saturable absorbers with improved optical properties (absorption band, modulation depth, nonlinear optical response). In this sense, we investigate the performance of indium nitride (InN) epitaxial layers with low residual carrier concentration (<1018 cm−3), which results in improved performance at telecom wavelengths (1560 nm). These materials have demonstrated a huge modulation depth of 23% and a saturation fluence of 830 µJ/cm2, and a large saturable absorption around −3 × 104 cm/GW has been observed, attaining an enhanced, nonlinear change in transmittance. We have studied the use of such InN layers as semiconductor saturable absorber mirrors (SESAMs) for an erbium (Er)-doped fiber laser to perform mode-locking generation at 1560 nm. We demonstrate highly stable, ultrashort (134 fs) pulses with an energy of up to 5.6 nJ.

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Passively mode-locked in Er-doped fiber laser based on semi-metallic InBi saturable absorber

Journal of Physics D Applied Physics ◽

10.1088/1361-6463/ac378e ◽

2021 ◽

Author(s):

Jianwei Hu ◽

Rong Huang ◽

Ziqiao Wei ◽

Minru Wen ◽

Fugen Wu ◽

...

Keyword(s):

Fiber Laser ◽

Modulation Depth ◽

Mode Locking ◽

Nodal Line ◽

Saturable Absorption ◽

Optical Nonlinearities ◽

Passive Mode ◽

Central Wavelength ◽

Two Dimensional Materials ◽

Er Doped

Abstract Two-dimensional materials have drawn great interest for their applications in mode-locking owning to their unique optical nonlinearities. However, most of these 2D materials are semi-conductor. In this study, a new kind of semimetal Indium bismuth (InBi) is reported which is a topological nodal-line semimetal with exotic physical properties. The InBi nanomaterials was prepared through liquid phase exfoliation method with average thickness of 32.8 nm. The saturable absorption property was measured and passive mode-locking operation was achieved successfully in Er-doped fiber laser. It exhibits a modulation depth of 3.21%, a saturable intensity of 100 MW/cm2, and a pulse width about 859.97 fs corresponding to the central wavelength of 1562.27 nm and 3-dB bandwidth of 2.98 nm. The experimental results open a new avenue for the use of semimetals InBi nanomaterials in lasers and photonics applications.

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Ultrafast mode-locking in highly stacked Ti3C2Tx MXenes for 1.9-μm infrared femtosecond pulsed lasers

Nanophotonics ◽

10.1515/nanoph-2020-0678 ◽

2021 ◽

Vol 10 (6) ◽

pp. 1741-1751

Author(s):

Young In Jhon ◽

Jinho Lee ◽

Young Min Jhon ◽

Ju Han Lee

Keyword(s):

High Performance ◽

Density Functional ◽

2D Materials ◽

Density Functional Theory Calculations ◽

Mode Locking ◽

Infrared Range ◽

Saturable Absorption ◽

Pulsed Lasers ◽

Saturable Absorbers ◽

Layer Stacking

Abstract Metallic 2D materials can be promising saturable absorbers for ultrashort pulsed laser production in the long wavelength regime. However, preparing and manipulating their 2D structures without layer stacking have been nontrivial. Using a combined experimental and theoretical approach, we demonstrate here that a metallic titanium carbide (Ti3C2Tx), the most popular MXene 2D material, can have excellent nonlinear saturable absorption properties even in a highly stacked state due to its intrinsically existing surface termination, and thus can produce mode-locked femtosecond pulsed lasers in the 1.9-μm infrared range. Density functional theory calculations reveal that the electronic and optical properties of Ti3C2Tx MXene can be well preserved against significant layer stacking. Indeed, it is experimentally shown that 1.914-μm femtosecond pulsed lasers with a duration of 897 fs are readily generated within a fiber cavity using hundreds-of-layer stacked Ti3C2Tx MXene saturable absorbers, not only being much easier to manufacture than mono- or few-layered ones, but also offering character-conserved tightly-assembled 2D materials for advanced performance. This work strongly suggests that as-obtained highly stacked Ti3C2Tx MXenes can serve as superb material platforms for versatile nanophotonic applications, paving the way toward cost-effective, high-performance photonic devices based on MXenes.

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Stable continuous-wave mode-locked laser from a 1645 nm Er:YAG ceramic oscillator

Applied Physics Express ◽

10.35848/1882-0786/ac481c ◽

2022 ◽

Author(s):

Yangyu Liu ◽

Xue Cao ◽

AnHua Xian ◽

Guangmiao Liu ◽

Wei zhou ◽

...

Keyword(s):

Solid State ◽

Pulse Width ◽

Peak Power ◽

Continuous Wave ◽

Modulation Depth ◽

Average Power ◽

Mode Locking ◽

Wave Mode ◽

Semiconductor Saturable Absorber ◽

Continuous Wave Mode

Abstract We demonstrate stable continuous-wave mode-locking (CWML) pulses around 1645nm by employing the home-made Er:YAG ceramic. By using a fiber laser and semiconductor saturable absorber mirror (SESAM) with modulation depth of 1.2%, we get ML pulses with the output average power up to 815 mW, the pulse width shortened as ~4 ps, and the peak power of 1.8 kW. With the SESAM of modulation depth of 2.4%, the second-order harmonic ML pulses were also obtained. As far as we know, this is the first report of CWML from Er3+-doped ceramics and also the shortest pulse duration in Er3+-doped solid-state oscillators.

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Research on the Response Characteristics of Vanadium Pentoxide Film to the Irradiation of Ultrafast Pulsed Laser

Nanomaterials ◽

10.3390/nano11082078 ◽

2021 ◽

Vol 11 (8) ◽

pp. 2078

Author(s):

Qianqian Shi ◽

Guodong Zhang ◽

Yuheng Wang ◽

Yu Lan ◽

Jiang Wang ◽

...

Keyword(s):

Refractive Index ◽

Laser Irradiation ◽

Vanadium Pentoxide ◽

Modulation Depth ◽

Ultrafast Laser ◽

Stable Phase ◽

Saturable Absorption ◽

Third Order ◽

The Third ◽

Structural Responses

Vanadium pentoxide (V2O5) is the most stable phase among many transition metal vanadium oxides, and has already been widely used in many fields. In this study, the morphological, structural, and optical responses of V2O5 film to ultrafast laser irradiation was investigated. The third-order nonlinear optical properties of V2O5 film were measured by common Z-scan technique, and the results showed that V2O5 film has self-defocusing and saturable absorption characteristics. The third-order nonlinear absorption coefficient and nonlinear refractive index were calculated to be −338 cm/GW and −3.62 × 10−12 cm2/W, respectively. The tunable saturated absorption with modulation depth ranging from 13.8% to 29.3% was realized through controlling the thickness of vanadium pentoxide film. V2O5 film was irradiated by ultrafast laser with variable pulse energy, and the morphological and structural responses of the V2O5 to the laser with different energy densities were investigated. The irreversible morphological and structural responses of V2O5 films to ultrafast laser irradiation was analyzed using the phase-contrast microscope and Raman spectrum. The chemical structure change from V2O5 to V6O13 was considered the main reason for refractive index modification.

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Ternary chalcogenide Ta2NiS5 nanosheets for broadband pulse generation in ultrafast fiber lasers

Nanophotonics ◽

10.1515/nanoph-2019-0350 ◽

2019 ◽

Vol 9 (8) ◽

pp. 2341-2349

Author(s):

Mengyuan Ma ◽

Jiantian Zhang ◽

Yao Zhang ◽

Xiaoli Wang ◽

Junli Wang ◽

...

Keyword(s):

Fiber Laser ◽

Laser Pulses ◽

Mode Locking ◽

Pulse Generation ◽

Ultrafast Laser ◽

Transition Metal Dichalcogenide ◽

Ultrafast Laser Pulses ◽

Ternary Chalcogenide ◽

Cavity Structure ◽

Er Doped

AbstractIn this article, a high-quality saturable absorber (SA) based on a two-dimensional ternary chalcogenide Ta2NiS5 nanosheet has been successfully fabricated and used in 1- and 1.5-μm spectral regions to generate ultrafast laser pulses. The Ta2NiS5-based SA is fabricated by mechanical exfoliation and sandwiched between two fiber ferrules to form a fiber-compatible SA. On the basis of the twin-detector technique, nonlinear optical absorption of the Ta2NiS5-SA is characterized by 64.7% and 11.95% modulation depths with 1.3 and 0.72 MW/cm2 saturation intensities at 1028 and 1570 nm, respectively. When Ta2NiS5-SA is integrated into Yb- and Er-doped fiber laser cavities, stable self-starting Q-switched pulses are observed. Furthermore, by adjusting the cavity structure and optimizing dispersion in the cavity, we obtain hybrid mode-locking and mode-locking fiber laser operation at 1029 and 1569 nm, respectively. These results validate the performance of Ta2NiS5 as a broadband SA for the generation of ultrafast laser pulses, offering new opportunities of ternary transition-metal dichalcogenide alloys in future photonic devices.

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Nonlinear plasmonic metasurfaces assisted laser mode locking

EPJ Web of Conferences ◽

10.1051/epjconf/202024314001 ◽

2020 ◽

Vol 243 ◽

pp. 14001

Author(s):

Lei Zhang ◽

Jiyong Wang ◽

Aurelien Coillet ◽

Philippe Grelu ◽

Benoit Cluzel ◽

...

Keyword(s):

Transfer Functions ◽

Incident Light ◽

Mode Locking ◽

Pulse Generation ◽

Nonlinear Regime ◽

Practical Implementation ◽

Saturable Absorption ◽

Geometrical Parameters ◽

Neuromorphic Circuits ◽

Saturable Absorbers

Plasmonic metasurfaces are artificial 2D layers made of subwavelength elementary cells, which give rise to novel wave properties that do not exist in nature. In the linear regime, their applications have been extensively studied, especially in wavefront manipulation for lensing, holography or polarization control. Interests in metasurfaces operating in nonlinear regime have also increased due to their ability to efficiently convert the fundamental light into harmonic frequencies and multiphoton emissions. Nevertheless, practical applications in the nonlinear regime have been rarely reported. In this study, we report that plasmonic metasurfaces with well-controlled polarimetric nonlinear transfer functions perform as saturable absorbers with modulation performances superior to that of other 2D materials. We employ planar nanotechnologies to fabricate 2D plasmonic metasurfaces with precise size, gap and orientation. We quantify the relationship between saturable absorption and the plasmonic resonances of the unit cell by altering the excitation power of pumping laser, the polarization of incident light and the geometrical parameters of the plasmonic metasurfaces. Finally, we provide a practical implementation by integrating the saturable metasurfaces into a fiber laser cavity and realize a stable self-starting ultrashort laser pulse generation. As such, this work sheds light on ultrathin nonlinear saturable absorbers for applications where nonlinear functions are required, such as in ultrafast laser or neuromorphic circuits.

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Carbon Nanomaterials Based Saturable Absorbers for Ultrafast Passive Mode-Locking of Fiber Lasers

Current Nanoscience ◽

10.2174/1573413715666191114150100 ◽

2020 ◽

Vol 16 (3) ◽

pp. 441-457

Author(s):

Chih-Hsien Cheng ◽

Gong-Ru Lin

Keyword(s):

Saturable Absorber ◽

Fiber Lasers ◽

Carbon Nanomaterials ◽

Modulation Depth ◽

Optical Nonlinearity ◽

Mode Locking ◽

Industrial Applications ◽

Passive Mode ◽

Saturable Absorbers ◽

Saturation Intensity

This paper emphasizes on overviewing the developing progress of the state-of-the-art carbon nanomaterial-based saturable absorbers for passively mode-locked fiber lasers, including carbon nanotube (CNT), graphene, graphite and other carbon nanomaterials. With reviewing the performances of these proposed candidates, the characteristic parameters required for initiating and stabilizing the passive mode-locked fiber lasers are summarized for comparison and discussion. At first, the basic characteristics such as saturation intensity and self-amplitude-modulation (SAM) coefficients of the CNT material with different-wall types are discussed in detail. In comparison, the single-wall CNT possesses optical nonlinearity better than double-wall CNT, whereas the doublewall CNT exhibits wavelength tenability and the multi-wall CNT fails to initiate mode-locking. Subsequently, different graphene saturable absorbers with slightly changing their optical properties made by various fabrication technologies are introduced to take over the role of typical CNT saturable absorber. The detailed analyses on graphene saturable absorber for developing various types of passively mode-locked fiber lasers are overviewed. At last, other new-aspect graphite and carbon nanomaterials related saturable absorbers have emerged because they reveal similar optical nonlinearity with graphene but exhibit cost-effectiveness and easy-production. When changing saturable absorber from graphene to other carbon nanomaterials, the modulation depth is decreased but the saturation intensity is concurrently enlarged because of the disordered structure with increased interlayer spacing and reduced graphene content. At the current stage, selecting carbon nanomaterials with high nonlinear absorbance and low saturated intensity for large SAM coefficient is the golden rule for passively mode-locked the fiber lasers in future academic and industrial applications.

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Ultrafast Fiber Lasers with Low-Dimensional Saturable Absorbers: Status and Prospects

Sensors ◽

10.3390/s21113676 ◽

2021 ◽

Vol 21 (11) ◽

pp. 3676

Author(s):

Pulak Chandra Debnath ◽

Dong-Il Yeom

Keyword(s):

Fiber Laser ◽

Fiber Lasers ◽

Near Infrared ◽

Modulation Depth ◽

Mode Locking ◽

Saturable Absorption ◽

Laser Applications ◽

Integration Schemes ◽

Pulsed Fiber Laser ◽

Low Dimensional

Wide-spectral saturable absorption (SA) in low-dimensional (LD) nanomaterials such as zero-, one-, and two-dimensional materials has been proven experimentally with outstanding results, including low saturation intensity, deep modulation depth, and fast carrier recovery time. LD nanomaterials can therefore be used as SAs for mode-locking or Q-switching to generate ultrafast fiber laser pulses with a high repetition rate and short duration in the visible, near-infrared, and mid-infrared wavelength regions. Here, we review the recent development of emerging LD nanomaterials as SAs for ultrafast mode-locked fiber laser applications in different dispersion regimes such as anomalous and normal dispersion regimes of the laser cavity operating in the near-infrared region, especially at ~1550 nm. The preparation methods, nonlinear optical properties of LD SAs, and various integration schemes for incorporating LD SAs into fiber laser systems are introduced. In addition to these, externally (electrically or optically) controlled pulsed fiber laser behavior and other characteristics of various LD SAs are summarized. Finally, the perspectives and challenges facing LD SA-based mode-locked ultrafast fiber lasers are highlighted.

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Generation and dynamics of soliton and soliton molecules from a VSe2/GO-based fiber laser

Nanophotonics ◽

10.1515/nanoph-2021-0543 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Benhai Wang ◽

Haobin Han ◽

Lijun Yu ◽

Yueyue Wang ◽

Chaoqing Dai

Keyword(s):

Numerical Simulation ◽

Fiber Laser ◽

Saturable Absorber ◽

Pulse Width ◽

Fiber Lasers ◽

Modulation Depth ◽

Mode Locking ◽

Pulse Interval ◽

Saturable Absorption ◽

Soliton Dynamics

Abstract Recently, in addition to exploring the application of new saturable absorber devices in fiber lasers, soliton dynamics has also become a focus of current research. In this article, we report an ultrashort pulse fiber laser based on VSe2/GO nanocomposite and verify the formation process of soliton and soliton molecules by the numerical simulation. The prepared VSe2/GO-based device shows excellent saturable absorption characteristics with a modulation depth of 14.3% and a saturation absorption intensity of 0.93 MW/cm2. The conventional soliton is obtained with pulse width of 573 fs, which is currently the narrowest pulse width based on VSe2-related material, and has a signal-to-noise ratio of 60.4 dB. In addition, the soliton molecules are realized based on the VSe2/GO for the first time and have a pulse interval of ∼2.2 ps. We study the soliton dynamics through numerical simulation and reveal that before the formation of the soliton, it undergoes multiple nonlinear stages, such as soliton mode-locking, soliton splitting, and soliton oscillation. Furthermore, the results of numerical simulation are agreed well with the experimental data. These results indicate that the VSe2/GO might be another promising saturable absorber material for ultrafast photonics, and deepen the understanding of soliton dynamics in ultrafast fiber lasers.

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Nonlinear optical property measurements of rhenium diselenide used for ultrafast fiber laser mode-locking at 1.9 μm

Scientific Reports ◽

10.1038/s41598-021-88735-1 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Jinho Lee ◽

Suhyoung Kwon ◽

Taeyoon Kim ◽

Junha Jung ◽

Luming Zhao ◽

...

Keyword(s):

Nonlinear Optical ◽

Modulation Depth ◽

Ring Cavity ◽

Mode Locking ◽

Saturable Absorption ◽

Closed Aperture ◽

Electronic Band ◽

Saturation Intensity ◽

Rhenium Diselenide ◽

Nonlinear Optical Device

AbstractAn experimental investigation into the nonlinear optical properties of rhenium diselenide (ReSe2) was conducted at a wavelength of 1.9 μm using the open-aperture and closed-aperture Z-scan techniques for the nonlinear optical coefficient (β) and nonlinear refractive index (n2) of ReSe2, respectively. β and n2 measured at 1.9 μm were ~ − 11.3 × 103 cm/GW and ~ − 6.2 × 10–2 cm2/GW, respectively, which to the best of our knowledge, are the first reported measurements for ReSe2 in the 1.9-μm spectral region. The electronic band structures of both ReSe2 and its defective structures were also calculated via the Perdew–Becke–Erzenhof functional to better understand their absorption properties. A saturable absorber (SA) was subsequently fabricated to demonstrate the usefulness of ReSe2 for implementing a practical nonlinear optical device at 1.9 μm. The 1.9-μm SA exhibited a modulation depth of ~ 8% and saturation intensity of ~ 11.4 MW/cm2. The successful use of the ReSe2-based SA for mode-locking of a thulium–holmium (Tm–Ho) co-doped fiber ring cavity was achieved with output pulses of ~ 840 fs at 1927 nm. We believe that the mode-locking was achieved through a hybrid mechanism of saturable absorption and nonlinear polarization rotation.

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