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Publisher Copyright: IEEE In this letter, indium phosphide (InP) nanowires (NWs) are fabricated by Au-nanoparticle assisted vapor-liquid-solid method and applied as a saturable absorber (SA) for continuous-wave (CW) mode-locked femtosecond Yb:KYW bulk laser. I-scan method was used to characterize the saturable absorption properties of the prepared InP NWs SA. Pulses as short as 394 fs with the repetition rate of 41.5 MHz and maximum average output power of 315 mW are achieved. To the best of our knowledge, this is the first demonstration of InP NWs working as SA for the fs-pulse generation in the solid-state bulk laser. The results indicate that InP NWs are a promising SA candidate for applications in ultrafast photonic devices.

Two-dimensional (2D) mono-elemental materials (Xenes) show remarkable potential in the fields of fundamental science and technology, have been regarded as a wide range of building blocks for electronic technologies due to their unique chemical, physical, electrical, and optical properties. Here, 2D tellurene/black phosphorus (Te/BP) heterojunctions are successfully fabricated through liquid-phase exfoliation (LPE) method. Their nonlinear optical absorption properties at 1.0, 2.0, and 2.8 μm have been studied by an open-aperture Z-scan method. The results revealed the excellent broadband saturable absorption responses of the prepared BP/Te heterojunctions, which are further confirmed by using them as saturable absorbers (SAs) for passively Q-switched all-solid-state lasers operating at 1.0, 2.0, and 2.8 μm, respectively. In particular, 1.04 μm continuous-wave (CW) mode-locked lasers with a pulse width of 404 fs is realized for the first time, to our best knowledge. Our work indicates that 2D Xenes especially 2D Xenes based heterojunctions have great potential in the fields of pulsed laser generation/modulation and other optoelectronic and photonic devices.

A novel disordered structure crystal has drawn intense interest as a promising ultrafast laser crystal host for its broad absorption and emission bands. Herein, a novel disordered crystal of Nd3+-doped CaYAl3O7 (CYAM) was successfully grown using the Czochralski method for the first time. The effective segregation coefficient of Nd3+ ions in CaYAl3O7 was calculated to be 0.76. To better understand the intrinsic optical properties, the transmission spectra and refractive index of pure CaYAl3O7 were measured. A systematic investigation of the crystal structure characteristics, fluorescence lifetime, and polarized absorption and emission cross-sections of the Nd:CYAM crystal at RT was reported. The maximal absorption cross-sections are 3.51 and 5.34 × 10−20 cm2 for π-polarization and σ-polarization, with a FWHM of 18 nm. The emission cross-sections of π- and σ-polarization are 5.97 and 4.55 × 10−20 cm2 with FWHM values of 14 and 14.4 nm, respectively. The results show that the Nd:CYAM crystal has broad, strong absorption and emission cross-sections. In particular, effective continuous-wave laser operation was realized with this crystal in the a-cut sample for the first time. A maximum output power of 714 mW was achieved, corresponding to an optical-to-optical conversion efficiency of 7.14% and a slope efficiency of 8.6%. Collectively, these results show that the Nd:CaYAl3O7 crystal is a promising disordered laser host.

Atomically thin Bi

We experimentally and theoretically investigate the noise-like pulse (NLP) generation in a nonlinear polarization rotation-based mode-locked Ho-doped fiber ring laser, which can optionally operate in the dual-wavelength regime. By carefully changing the pump power and polarization state, the dual-wavelength NLP regime at 2041.9 and 2083.3 nm is finally achieved, which corresponds to a pulse energy of 11.84 nJ and a pulse duration of 849 fs. It is believed to be the first report on the dual-wavelength NLP operation from the previously reported Ho-doped fiber lasers.

Cascade transitions of Ho3+:5I6→5I7 and 5I7→5I8 provide a platform for a dual-wavelength mid-infrared (MIR) laser. In this paper, a continuous wave cascade MIR Ho:YLF laser operating at 2.1 and 2.9 µm is realized at room temperature. The total output power of 929 mW with 778 mW at 2.9 µm and 151 mW at 2.1 µm is obtained under the absorbed pump power of 5 W. Compared to the non-cascade mode, 2.9-µm lasing threshold is reduced by 10.3% and the slope efficiency is increased by 76.1% with the supports of cascade lasing at 2.1 µm. However, 2.9-µm lasing is the key population accumulation of the 5I7 level, which thus efficiently reduces the threshold and improves the output power of the 2.1-µm laser. Our results put forward a way for generating cascade dual-wavelength MIR lasing in Ho3+-doped crystals.

The modified Frantz–Nodvik equation considering the pulse repetition rate (PRR) for continuous-wave end-pumped picosecond laser amplifier is theoretically developed for the first time by analogizing Q-switch theory and solving rate equations. Based on the modified Frantz–Nodvik equation, a simple finite-element slice model is established to simulate the output characteristics of the end-pumped high-repetition-rate picosecond amplifier. Moreover, the validity of the theory and model is well verified by the experimental results of a two-staged diode-end-pumped Nd : YVO4 amplifiers using a picosecond fiber laser with adjustable PRRs as the seed source. The agreement between the experimental and theoretical results illustrates that the as-developed pulse amplification theory and model are a powerful tool for designing and optimizing adjustable-high-repetition-rate solid-state picosecond laser amplifiers.

Indium arsenide phosphide (InAsP) nanowires (NWs), a member of the III–V semiconductor family, have been used in various photonic and optoelectronic applications thanks to their unique electrical and optical properties such as high carrier mobility and adjustable band gap. In this work, we synthesize InAsP NWs and further explore their nonlinear optical properties. The ultrafast carrier dynamics and nonlinear optical response are thoroughly studied based on the nondegenerate pump probe and Z-scan experimental measurements. Two different characteristic carrier lifetimes ( ∼ 2 and ∼ 15 ps ) from InAsP NWs are observed during the excited-carrier relaxation process. Based on the physical model analysis, the relaxation process can be ascribed to the carrier cooling process via carrier-phonon scattering and Auger recombination. In addition, based on the measured excited-carrier lifetime and Pauli-blocking principle, we discover that InAsP NWs show strong saturable absorption properties at the wavelengths of 532 and 1064 nm. Last, we demonstrate for the first time a femtosecond ( ∼ 426 fs ) solid-state laser based on an InAsP NWs saturable absorber at 1.04 μm. We believe that our work provides a better understanding of the InAsP NWs optical properties and will further advance their photonic applications in the near-infrared range.

A saturable absorber (SA) based on niobium diselenide (NbSe2), which is a layered transition metal dichalcogenide (TMD) in the VB group, is fabricated by the optically driven deposition method, and the related nonlinear optical properties are characterized. The modulation depth, saturable intensity, and nonsaturable loss of the as-prepared NbSe2 nanosheet-based SA are measured to be 16.2%, 0.76 MW/cm2, and 14%, respectively. By using the as-fabricated NbSe2 SA, a highly stable, passively Q-switched, erbium-doped, all-fiber laser is realized. The obtained shortest pulse width is 1.49 μs, with a pulse energy of 48.33 nJ at a center wavelength of 1560.38 nm. As far as we know, this is the shortest pulse duration ever obtained by an NbSe2 SA in a Q-switched fiber laser.

A diode-pumped passively mode-locked Tm3+-doped yttrium lithium fluoride (YLF) bulk laser at ∼2.3 µm is successfully achieved by using a kind of GaAs-based semiconductor saturable absorber mirror (SESAM). When working in the continuous mode-locking regime, stable ultrashort pulses with a duration of 52.5 ps and a repetition rate of 67 MHz are generated, with a corresponding maximum dual-output power of 284 mW. The radio-frequency spectrum of the output pulses demonstrates a high signal-to-noise ratio of 60 dB. To the best of our knowledge, this is the first report of a diode-pumped all-solid-state passively mode-locked thulium-doped laser at ∼2.3 µm.

High-quality gold nanospheres (Au NPs) were transferred to a sapphire substrate. The balanced twin-detector measurement technique was used to study the saturable absorption properties of the Au NPs. With the as-prepared Au NPs as a saturable absorber (SA), an efficient passively Q-switched laser was realized at 1.93 μm. Under an absorbed pump power of 4.5 W, a maximum output power of 400 mW was obtained with the shortest pulse width of 410 ns and repetition rate of 126 kHz. The results indicate that Au NPs are promising candidates as SAs for mid-infrared laser pulse generation.

A ternary transitional metal dichalcogenides alloy material, molybdenum sulphoselenide (MoSSe), has been successfully fabricated and used as a saturable absorber (SA) for a passively Q-switched (PQS) Tm:YAP bulk laser operating at $2.0~\mu \text{m}$ for the first time, to best of our knowledge. The open aperture Z-scan method was used to characterize the saturable absorption properties of the prepared MoSSe SA. The maximum average output power and pulse repetition rate, shortest pulse width, highest single pulse energy, and highest pulse peak power of this laser were 2.26 W, 95 kHz, 303 ns, $24.2~\mu \text{J}$ , and 80 W, respectively. The results are distinguished from other two-dimensional materials-based $2.0~\mu \text{m}$ PQS lasers, indicating that MoSSe could be a promising material for generating high power and short pulse width lasers in the $2.0~\mu \text{m}$ spectral range.

Single-crystal fiber (SCF) combines the advantages of bulk crystal and glass fiber gain media and shows broad application prospects in all-solid-state lasers. In this work, high-quality crack-free Nd:YAG SCFs with diameters of 0.8–1 mm were successfully grown by the micro-pulling-down (μ-PD) method. The as-grown SCFs showed homogeneous Nd3+ distribution, with a diameter fluctuation of less than 5%. The X-ray Laue patterns on the different crystal positions also revealed good crystalline consistency. Moreover, the core stress problems were investigated in terms of growth orientation to improve the crystal quality, and seed crystals with orientation of , and to 15° were used for crystal growth. Continuous-wave laser operations at 1064 nm were realized with the as-grown Nd:YAG SCFs. The maximum output of 8.32 W with a laser beam quality factor M2 = 1.08 was achieved.

Herein, bulk single crystals of Er:Y3Sc2Ga3O12 (Er:YSGG) with a maximum diameter of 35 mm or a maximum length of 100 mm were successfully grown by the Czochralski method using a 60 mm diameter crucible. The high-resolution X-ray diffraction and optical interferometry results indicated that the as-grown crystals were of high quality. The crystalline perfection of the as-grown crystal was evaluated to be 20.58′′ via the FWHM of the rocking curve, and the optical homogeneity RMS was in the order of 10−6. A continuous wave laser of the Er:YSGG crystal operating at 2798.7 nm has been demonstrated. Moreover, a maximum output power of 745 mW has been realized. The achieved maximum slope efficiency is 31.5%, which is, to date, the highest slope efficiency in the Er:YSGG crystal lasers operating at ∼2.8 μm.

Niobium carbide (

In this paper, two-dimensional (2D) few-layer Ta2CTx nanosheets are fabricated by liquid phase exfoliation (LPE) method. The nonlinear optical absorption properties are studied by Z-scan and I-scan techniques, revealing excellent saturable absorption response with an effective nonlinear absorption coefficient of -92.2 cm/MW@1064 nm. The saturation intensity and modulation depth for 1064 nm and 1550 nm are determined to be 79 and 51 MW/cm2, 9.9% and 4.5%, respectively. Furthermore, by decorating few-layer Ta2CTx nanosheets onto microfiber, few-layer Ta2CTx saturable absorber (SA) is fabricated and applied in Yb-doped and Er-doped fiber lasers (YDFLs and EDFLs). Not only a normal mode-locked operation but also square-wave pulse (SWP) are realized by increasing the length of the laser cavity at 1.5 µm, highlighting the great potential of few-layer Ta2CTx nanosheets as an optical modulator. The maximum pulse duration of 5.56 ns is also the widest SWP width that can be realized with 2D materials without filtering device in the cavity. Our work provides a platform for exploring novel SAs materials and nonlinear phenomena in mode-locked fiber lasers.

A modified Frantz-Nodvik (F-N) equation and a simple one-dimensional unfolded slicing model for numerically simulating high-power Innoslab picosecond amplifier are developed for the first time. The anisotropic stimulated emission cross-section of laser crystal, the influence of the tilted optical path, the spatial overlap of the seed and pump laser, as well as the pump absorption saturation effect are considered. Based on the as-developed model, 4-, 6- and 8-pass schemes high-power Nd:YVO4 Innoslab picosecond amplifiers are designed with output powers of 76.2 W, 81.4 W, and 85.5 W, respectively. The experimental results agree well with that of numerical simulation, indicating that our model is a powerful tool and paves a new way for designing and optimizing high-power Innoslab picosecond laser amplifier.

In this paper, a high-power and high-efficiency 4.3 µm mid-infrared (MIR) optical parametric oscillator (OPO) based on ZnGeP2 (ZGP) crystal is demonstrated. An acousto-optically Q-switched Ho:Y3Al5O12 laser operating at 2.1 µm with a maximum average output power of 35 W and pulse width of 38 ns at a repetition rate of 15 kHz is established and employed as the pump source. A doubly resonant OPO is designed and realized with the total MIR output power of 13.27 W, including the signal and idler output power of 2.65 W at 4.07 µm and 10.62 W at 4.3 µm. The corresponding total optical-to-optical and slope efficiencies are 37.9% and 67.1%, respectively. The shortest pulse width, beam quality factor, and output power instability are measured to be 36 ns, Mx2=1.8, My2=2.0, and RMS

Localized surface plasmon resonance (LSPR) of metallic nanoparticles (NPs) can generate and enhance the nonlinear optical (NLO) response and has been widely used in biosensing, optical bistability, optical switch, and modulator, surface-enhanced spectroscopies, etc. Here, the two-dimensional (2D) Au & Ag hybrid plasmonic NP network (Au & Ag HPNN) were synthesized by assembling Au and Ag NPs in ethanol solvent and transferring onto a CaF2 substrate. The frequency-domain finite element method (FEM) simulations were performed to explore their LSPR properties, demonstrating the broadband optical responses throughout visible, near-infrared and mid-infrared regions. The ultrafast carrier relaxation times were determined to be 3.9, 5.6, and 8.6 ps, while the nonlinear absorption coefficients were −1.12 × 104, −1.71 × 104, and −2.54 × 104 cm/GW, respectively, for the three wavelengths matching the LSPRs peaks at 1.0, 2.0, and 3.0 μm bands. Furthermore, passively Q-switched (PQS) solid-state lasers operating at 1062.8, 1990.8, and 2947 nm were demonstrated with 2D Au & Ag HPNN based saturable absorbers. This work not only reveals desirable ultrafast broadband NLO responses of 2D HPNN, but also provides a platform for investigating their applications in nanophotonic devices., This work was supported by the National Research Foundation of China (Grant No. 61675116, 61975095, 61775093, 615751109), Development Program for Public Welfare in Shandong (2017GGX20134), and the Young Scholars Program of Shandong University (Grant No.2017WLJH48). The Chinese Scholarship Council fellowship (201806220063) to W.C. Duan is also acknowledged.

An electro-optically (EO) $Q$Q-switched Tm:YAP laser with high peak power was demonstrated based on a ${{\rm La}_3}{{\rm Ga}_5}{{\rm SiO}_{14}}$La

Efficient continuous wave (CW) and passively Q-switched Ho3+,Pr3+:LiLuF 4 (Ho,Pr:LLF) laser operating at 2.95 μ m were realized using a 1150-nm Raman fiber laser as the pump source. A CW output power as high as 1.15 W, which we believe to be the highest one ever achieved from Ho 3+-doped bulk laser emission around 3 μ m, corresponds to an optical-to-optical conversion efficiency of 14.5% and a slope efficiency of 15.5%, respectively. A high-quality saturable absorber (SA) based on multilayered black phosphorus (BP) nanosheet film deposited on a CaF2 substrate was successfully fabricated and employed. Under the absorbed pump power of 7.36 W, the shortest pulse width of 194.3 ns was obtained, which is the shortest among the two-dimensional materials as SA around 3 μ m. The results not only indicated that Ho,Pr:LLF crystal would be a promising mid-infrared (MIR) gain medium for obtaining high power output, but verified that the multilayered BP is a promising optical modulator for generating short pulses in MIR spectral range.

By using a few-layer black phosphorus (BP) as the saturable absorber (SA), a laser-diode end-pumped stable Q-switched Nd:GdVO4 laser operating at 1.3 μm was realized. A maximum average output power of 452 mW was obtained at 2.22 W absorbed pump power, corresponding to a 34.5% slope efficiency. The shortest pulse width, highest pulse repetition rate, and largest peak power were determined to be 72 ns, 625 kHz, and 10.04 W, respectively. To the best of our knowledge, this pulse duration was the shortest ever reported for passive Q-switched bulk lasers based on two-dimensional materials at 1.3 μm. Results suggested that BP can be used to achieve short laser pulses with high repetition rate at 1.3 μm spectral region.

Highly efficient continuous-wave (CW) and passively Q-switching Er:YSGG lasers at around $2.8~\mu \text{m}$ were demonstrated. In the CW regime, a maximum output power was 514 mW with the dual-wavelength of 2795 and 2825 nm. The slope efficiency and optical-optical conversion efficiency were as high as 31% and 23%, respectively. Adopting black phosphorus as saturable absorber, a maximum output power of the passively Q-switched Er:YSGG laser was 240 mW, with a corresponding slope efficiency up to 15.8%. The shortest pulse duration was 293 ns, and the repetition rate was 109.1 kHz. The results indicated that Er:YSGG crystal would be a promising mid-infrared gain medium for high-efficiency laser operation.

Black phosphors (BP) nano-materials have been extensively investigated in the past years. However, the character of easily oxidizable limits BP's stability. Here a long-term-stable tunable Q-switched fiber laser with BP polymer composite (polyvinyl alcohol, PVA) as saturable absorber is realized. The modulation depth and the saturation power intensity of the BP-PVA film are 8.3% and 7.9 MW/cm2, respectively. A high average output power of 12.03 mW is obtained under the pump power of 400 mW. The shortest pulse width and maximum single pulse energy are 1.365 μs and 148.63 nJ, respectively. Meanwhile, the output spectra have a 2.5-nm blue shift when the pump power increases. The results prove that as a Q-switcher, BP polymer composite has a good performance on high power and excellent stability pulsed laser.

1T-titanium selenide (1T-TiSe2), a representative of 1T phase transition metal dichalcogenides (TMDs), exhibits semimetallic behaviour with a nearly zero bandgap structure, which makes it a promising photoelectric material. A high-quality multilayer 1T-TiSe2 saturable absorber (SA) is successfully fabricated by a combination of liquid phase exfoliation and the spin coating method. The broadband nonlinear saturable absorption properties of the prepared 1T-TiSe2 SA are investigated by using the open aperture (OA) Z-scan method. Passively Q-switched (PQS) all-solid-state lasers with different bulk crystals at the wavelengths of 1.0, 1.3, 2.0 and 2.8 μm are realised based on the 1T-TiSe2 SA. To the best of our knowledge, this is the first presentation of the application of a 1T-TiSe2 material to all-solid-state bulk lasers. The results indicate that 1T-TiSe2 could be an alternative broadband SA for solid-state pulsed lasers and exhibits promising potential applications in mode-locked ultrafast lasers.

In this study, we operated a novel bulk laser: a dual-end-pumped electro-optically (EO) Q-switched Ho, Pr:YLF laser at 2945.9 nm with a repetition rate of kHz level. The shortest pulse duration of 25.2 ns was obtained at the repetition rate of 500 Hz, corresponding to a single pulse energy of 0.4 mJ and a peak power of 15.9 kW. A maximum output power of 268 mW was delivered at the repetition rate of 1.5 kHz. The beam quality factors of the EO Q-switched Ho, Pr:YLF laser at the maximum output power were Mx 2 = 1.50 and My 2 = 1.54 in x- and y- directions, respectively. The long-term output power instability was measured to be ± 1.5% (RMS) within five hours. The achieved results indicated the promising potential of Ho, Pr: YLF crystals for high repetition rate Q-switched mid-infrared laser pulse generation very well.

In this Letter, a high-quality saturable absorber (SA) based on a multilayered two-dimensional ternary chalcogenide Ta

Here, few-layered W2C nanosheets and microfiber-based few-layered W2C-SA are fabricated by the magnetron sputtering deposition method. The third-order nonlinear optical responses of the prepared 2D W2C nanosheets are investigated by the Z-scan method with βeff and n2 determined to be −88.2 cm/MW and −1.112×10−13 m2/W, respectively, revealing its excellent nonlinear saturable absorption properties and optical modulation capabilities. In addition, by incorporating microfiber based few-layered W2C-SA into Yb-doped and Er-doped fiber lasers (YDFLs and EDFLs), the passively mode-locked operations at the central wavelength of 1035.1 and 1562 nm are realized, respectively. In addition, multi-soliton bound mode-locked operation in EDFLs with soliton pulses up to 36 is realized. Our results not only demonstrate the capability of few-layered W2C as a wideband optical modulator, but also provide a practical approach to explore soliton dynamics in fiber lasers.

In this paper, the absorption and fluorescence spectra of Er3+, Pr3+ co-doped LiYF4 (Er,Pr:YLF) crystal were measured and analyzed. The Pr3+ co-doping was proved to effectively enhance the Er3+:I411/2→I413/2 mid-infrared transition at the 2.7 µm with 74.1% energy transfer efficiency from Er3+:I413/2 to Pr3+:F34. By using the Judd–Ofelt theory, the stimulated emission cross section was calculated to be 1.834×10−20 cm2 at 2685 nm and 1.359×10−20 cm2 at 2804.6 nm. Moreover, a diode-end-pumped Er,Pr:YLF laser operating at 2659 nm was realized for the first time, to the best of our knowledge. The maximum output power was determined to be 258 mW with a slope efficiency of 7.4%, and the corresponding beam quality factors Mx2=1.29 and My2=1.25. Our results suggest that Er,Pr:YLF should be a promising material for 2.7 µm laser generation.

Mid-infrared (MIR) laser sources operating in the 2.7–3 µm spectral region have attracted extensive attention for many applications due to the unique features of locating at the atmospheric transparency window, corresponding to the “characteristic fingerprint” spectra of several gas molecules, and strong absorption of water. Over the past two decades, significant developments have been achieved in 2.7–3 µm MIR lasers benefiting from the sustainable innovations in laser technology and the great progress in material science. Here, we mainly summarize and review the recent progress of MIR bulk laser sources based on the rare-earth ions-doped crystals in the 2.7–3 µm spectral region, including Er3+-, Ho3+-, and Dy3+-doped crystalline lasers. The outlooks and challenges for future development of rare-earth-doped MIR bulk lasers are also discussed.

Niobium carbide ( N b 2 C ), a novel two-dimensional MXene material, has attracted much attention due to its outstanding electronic and optical properties. In this work, a microfiber-based few-layer N b 2 C saturable absorber (SA) is fabricated by the magnetron sputtering deposition technique. The reverse saturable absorption (RSA) response of few-layer N b 2 C nanosheets is observed with I-scan measurements. The square-wave pulses (SWPs) are generated by using the as-prepared microfiber-based few-layer N b 2 C SA in an erbium-doped fiber laser. The SWP width increases from 0.33 to 2.061 ns with the single pulse energy increases linearly up to 0.89 nJ while the amplitude remains as a constant. In addition, nonlinear polarization rotation mode-locking fiber lasers with different cavity lengths are constructed to explore the formation conditions of SWP. Our results indicate that the RSA effect of the few-layer N b 2 C nanosheets plays a decisive role in the formation of the SWP.

A room-temperature highly efficient Tm:YAP laser pumped MgO:PPLN optical parametric oscillator operating at 3.87 µm near degeneracy is demonstrated. The pump source is an acousto-optical (AO) Q-switched Tm:YAP laser, which delivers a maximum output power of 6.17 W with a pulse duration of 45 ns and a repetition rate of 6 kHz. The temperature dependent wavelength tuning characteristics of the PPLN-OPO is investigated, and a maximum OPO output power of 1.2 W at around 3.87 µm is achieved at 35°C, corresponding to an optical-optical conversion efficiency of 19.4%. To the best of our knowledge, this is the maximum output power ever reported from 2 µm waveband laser pumped 3-5 µm MgO:PPLN OPOs.

We report on the crystal growth, structure, thermal, spectral properties, and laser performance of a novel disordered crystal, Yb3+-doped CaYAl3O7 (Yb: CYAM). The complete set of anisotropic thermal properties were systematically studied. Due to the random distributions of Y3+ and Ca2+ ions, the internal disordered structure determines a significant broadening of the absorption (FWHM=25 nm) and emission (FWHM=60 nm) bands. Polarized absorption, emission and gain cross-section spectra are determined. A maximum σem at 1011 nm for π polarization was calculated to be 0.57 × 10−20 cm2. CW laser operation at 1.06 µm with the c-cut sample has been demonstrated. A maximum power of 505 mW was achieved at 1026.5 nm, corresponding to the slope efficiency and optical conversion efficiency being 12.5% and 6.7%, respectively. Yb: CYAM crystal reveals its superiority and potentiality in the ultrashort pulse laser field.

An in-band end-pumped LGS electro-optically (EO) Q-switched Ho:YAP laser has been investigated and demonstrated. The LGS crystal based on EO modulator was designed to operate in pulse-on mode with a 1/4 wave voltage of 2400 V, which was the lowest driving voltage at 2 μm wavelength for LGS crystal as far as we know. Under continuous-wave (CW) regime, a maximum average output power of 6.5 W was obtained from the Ho:YAP laser with a slope efficiency of 50.6% when an incident pump power was 16 W. When running in EO Q-switching regime, a maximum output power of 4 W was obtained with a single pulse energy of 1 mJ and a pulse width of 33 ns at a repetition rate of 4 kHz. At the repetition rate of 2 kHz, the maximum single pulse energy of 1.5 mJ and the shortest pulse width of 23 ns were achieved, corresponding to a pulse peak power of as high as 65 kW.

In this article, a high-power diode-end-pumped passively Q-switched (PQS) Tm:YAP laser is reported with novel two-dimension (2D) molybdenum ditelluride (MoTe

Few-layered titanium carbide (Ti