RESUMEN
Blue-laser-diode-pumped Pr3+-based continuous-wave (CW) green lasers have aroused growing research interest in developing optoelectronic applications and deep ultraviolet laser sources due to their simple and compact structural design. However, the obstacle of thermally induced effects limits the available output power of Pr3+-based green lasers. Herein, combined with the theoretical analysis and experimental feedback, we effectively adjust the heat distribution inside the Pr3+:LiYF4 gain crystal by optimizing the crystal dimension and doping concentration. The excellent mode matching between the pump and green lasers is achieved under the consideration of thermally induced effects, yielding a maximum CW output power of 7.56 W. To the best of our knowledge, this is the largest output power of Pr3+-based CW green lasers so far. Moreover, the obtained green laser demonstrates excellent output stability (RMS = 1.27%) and beam quality (M2 = 1.30 × 1.12) under the lasing operation state with the maximum output power. We hope that this study can provide a feasible paradigm for developing blue-laser-diode-pumped visible lasers, especially for high-power lasers.
RESUMEN
Yellow lasers at 590â nm have many extensive applications in our daily life, but extremely difficult to attain by traditional solid-state laser technology, owing to the absence of highly-efficient transition channels at this spectral range. In this work, we proposed a cooperative lasing mechanism to obtain the yellow light emission, with multiphonon-assisted electronic transitions and phase-matched frequency-doubling. Based on the predictable configurational coordinate model, we can calculate the multiphonon-assisted emission step-by-step. Using Yb3+-doped La2CaB10O19 crystal as an example, it is capable of producing yellow laser at 581-590â nm, with a maximum output power of 4.83 W and a high slope efficiency of 31.6%. To the best of our knowledge, it represents the highest power of solid-state yellow laser realized in one single crystal pumped by a laser diode. This power scaling can be assigned to the amplified phonon-assisted emission beyond the fluorescence spectrum, and optimized crystal angle for phase-matching condition. Such a compact, low-cost, and high-power laser device, provides an alternative candidate for the spectral "yellow-gap" where no practical solid-state laser exists at present.
RESUMEN
An approach to obtain a yellow laser is demonstrated for the first time to our knowledge by the employment of an Nd3+-doped YVO4 crystal and a LBO frequency-doubling crystal. Differing from the previous stimulated self-Raman radiation of Nd:YVO4, a direct 1176â nm lasing, without a high-intensity intracavity 1064â nm laser, was realized by utilizing an electron-phonon coupling effect and amplifying the thermally activated vibronic transitions. Combining with intracavity frequency-doubling, a yellow laser at 588â nm was obtained. At the pump power of 14.3â W, the output power of the yellow laser was 1.17â W, corresponding to a diode-to-visible efficiency of 8.2%. Moreover, for the first time, the yellow laser at 584â nm with output power of 164â mW was realized by tuning the filter, indicating the great potential of such an electron-phonon coupling laser for a wavelength extension in the yellow regime.
RESUMEN
Cationic substitution demonstrates significant potential for regulating structural dimensionality and physicochemical performance owing to the cation-size effect. Leveraging this characteristic, this study synthesized a new family of K4AeP2S8 (Ae = alkaline earth elements: Mg, Ca, Sr, and Ba) thiophosphates, involving the substitution of Ae2+ cations. The synthesized compounds crystallized in distinct space groups, monoclinic P2/c (Ae = Mg) versus orthorhombic Ibam (Ae = Ca, Sr, and Ba), exhibiting intriguing dimensionality transformations from zero-dimensional (0D) [Mg2P4S16]8- clusters in K4MgP2S8 to 1D ∞[AeP2S8]4- chains in other K4AeP2S8 thiophosphates owing to the varying ionic radii of Ae2+ cations, Ae-S bond lengths, and coordination numbers of AeSn (Mg: n = 6 versus other: n = 8). Experimental investigations revealed that K4AeP2S8 thiophosphates featured wide optical bandgaps (3.37-3.64 eV), and their optical absorptions were predominantly influenced by the S 3p and P 3s orbitals, with negligible contributions from the K and Ae cations. Notably, within the K4AeP2S8 series, birefringence (Δn) increased from K4MgP2S8 (Δn = 0.034) to other K4AeP2S8 (Δn = 0.050-0.079) compounds, suggesting that infinite 1D chains more significantly influence Δn origins than 0D clusters, thus offering a feasible approach for enhancing optical anisotropy and exploring potential new birefringent materials.
RESUMEN
Surface nonlinear optics are essential for developments in integrated photonics and micro/nano optoelectronics. However, the nonlinear optical conversion efficiency on a surface is restricted by the finite nonlinear susceptibility of matter and the intrinsic atomic-layered interaction length between light and matter. In this work, based on an angular engineering strategy, it is demonstrated that the centrosymmetric topological semimetal HfGe0.92Te crystal has a giant and anisotropic surface second-order nonlinear susceptibility up to 5535 ± 308 pm V-1 and exhibits efficient and unprecedented second-harmonic generation (SHG). The maximum optical conversion efficiency is found to be up to 3.75, which is 104 times higher than that obtained from a silicon surface. Because of the linear dispersion over a wide range of energies around the Dirac points, this high conversion efficiency can be maintained with SHG wavelengths ranging from the visible region (779 nm) to the deep-UV region (257.5 nm). This study can facilitate the development of topological photonics and integrated nonlinear photonics based on topological semimetals.