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High-harmonic mode-locking based on strong optoacoustic interactions in solid-core photonic crystal fiber (PCF) has been an established mechanism to achieve a stable GHz repetition rate in a conventional soliton fiber laser, in which a uniform pulse sequence is self-locked to the acoustic core-resonance of the PCF with a specific harmonic order. However, due to the finite bandwidth of the acoustic core-resonance, there may be multiple choices of harmonic order within the resonance bandwidth that could lead to uncertainties in the resultant harmonic order. In this work, we report observations of dynamic self-adaptation of the pulses in the laser cavity towards a stable harmonic order when the cavity is initially set at a neighboring less stable harmonic order. We observed that self-adaptation can occur spontaneously towards either higher or lower harmonic order depending on the initial condition. We observed rich dynamics during the self-adaptation process namely transient pulse sliding, random pulse collisions, and pulse drop-outs. This work provides experimental insight into the robustness of the self-locked repetition rate in optoacoustic mode-locking, and we believe will be useful in understanding and controlling harmonically mode-locked lasers.
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http://dx.doi.org/10.1364/OE.547755 | DOI Listing |
Npj Nanophoton
September 2025
Chair in Hybrid Nanosystems, Nanoinstitute Munich, Faculty of Physics, Ludwig-Maximilians-Universität München, Munich, Germany.
Second-order nonlinear optical processes are fundamental to photonics, spectroscopy, and information technologies, with material platforms playing a pivotal role in advancing these applications. Here, we demonstrate the exceptional nonlinear optical properties of the van der Waals crystal 3R-MoS, a rhombohedral polymorph exhibiting high second-order optical susceptibility ( ) and remarkable second-harmonic generation (SHG) capabilities. By designing high quality factor resonances in 3R-MoS metasurfaces supporting quasi-bound states in the continuum (qBIC), we first demonstrate SHG efficiency enhancement exceeding 10.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Laboratory for Fundamental BioPhotonics (LBP), Institute of Bioengineering (IBI), School of Engineering (STI), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne CH-1015, Switzerland.
Life requires chemical chiral specificity. The emergence of enantioselectivity is unknown but has been linked to diverse scenarios for the origin of life, ranging from an extraterrestrial origin to polarization-induced effects, and magnetic field-induced mineral templating. These scenarios require an originating mechanism and a subsequent enhancement step, leading to widespread chiral specificity.
View Article and Find Full Text PDFLight Sci Appl
September 2025
Department of Materials Science and Engineering, Centre for Functional Photonics, and Hong Kong Branch of National Precious Metals Material Engineering Research Centre, City University of Hong Kong, Hong Kong, China.
Observation of the second-harmonic generation (SHG) from subwavelength metallic structures is often hindered by the interrelations of higher-order multipolar contributions. In particular, the magnetic Lorentz contribution to SHG is often neglected due to the ineffective magnetic field enhancement in electrically resonant structures. Here, we demonstrate a strong Lorentz-driven SHG output at the plasmon-induced magnetic dipolar resonance in inversion-symmetry-broken plasmonic nanocavities.
View Article and Find Full Text PDFJ Phys Chem Lett
September 2025
Hunan Key Laboratory of Nanophotonics and Devices, School of Physics, Central South University, Changsha 410083, People's Republic of China.
NbOCl has garnered interest owing to its second-order nonlinear optical properties, but the influence of thickness on its third-harmonic generation (THG) and excited-state dynamics has not been fully investigated. Here, mechanically exfoliated NbOCl flakes were found to produce THG and second-harmonic generation (SHG), simultaneously, and to show a nonmonotonic dependence on sample thickness. The increase in thickness leads to a decrease in the bandgap.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Institute of Inorganic and Analytical Chemistry, University of Münster, Corrensstrasse 28/30, 48149 Münster, Germany.
Materials exhibiting coexisting exploitable properties often result in especially attractive behavior from both fundamental and applied perspectives. In particular, magnetoelectric materials combining ferroelectric and magnetic properties are increasingly becoming paramount nowadays. Here, we show that FeH(PO) exhibits proton conductivity and the coexistence of magnetic and polar structural features, suggesting that such frameworks may be of broader interest beyond the field of proton conductors.
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