J. Eur. Opt. Society-Rapid Publ. 2025, 21, E1 Ó The Author( s), published by EDP Sciences, 2025 https:// doi. org / 10.1051 / jeos / 2025041 Available online at: https:// jeos. edpsciences. org
Journal of the European Optical Society-Rapid Publications
EOSAM 2024 Guest editors: Luca De Stefano and Raffaele Velotta
EDITORIAL
Editorial
Luca De Stefano 1,* and Raffaele Velotta 2,*
1 Institute of Applied Sciences and Intelligent Systems – Unit of Naples-National Research Council, Via P. Castellino 111, 80131, Italy 2 Dipartimento di Fisica“ E. Pancini”- Università di Napoli“ Federico II”, Via Cintia, 26 Ed. 6, 80126 Napoli, Italy
The European Optical Society Annual Meeting, EOSAM 2024, covered the full breadth of optics and photonics through a rich combination of topical meetings, focused sessions, tutorials, and industrial presentations. The 12th edition of the event was organized onsite in Napoli, Italy, from 9 to 13 September 2024, and was hosted by the University of Napoli Federico II, one of the oldest public universities in the world. The city with its unique blend of history, culture, and Mediterranean energy, provided an ideal setting for dialogue and collaboration within the international optics community. The conference brought together nearly 500 participants from 36 countries, including researchers, students, industry professionals, and leading experts. With 470 accepted contributions across 13 topical meetings and 4 focused sessions, EOSAM 2024 offered a comprehensive view of current developments in fields such as nonlinear optics, frequency combs, ultrafast science, optical coatings, beam shaping, metrology, and resonator physics. The scientific program was complemented by high-level plenary talks, a poster session, a vibrant exhibition, and special industry events. The meeting confirmed the growing impact of optics and photonics as key enabling technologies for scientific progress, sustainable development, and innovation in Europe and beyond.
Following the 12th EOSAM, this issue of the Journal of the European Optical Society – Rapid Publications( JEOS-RP) gathers fifteen papers that reflect the scientific diversity and vitality of the conference. Topics range from nonlinear optics and ultrafast dynamics to advanced optical coatings, from microfabrication strategies to resonator theory and metrology. This collection includes thirteen original research articles, one short communication, and one review article.
A central thread in this issue is the exploration of nonlinear and ultrafast phenomena. The review by Laurell et al. provides an authoritative and historically informed overview of backward-wave optical parametric oscillators( BWOPOs), discussing their fundamental principles, design strategies, and applications in tunable coherent sources [ 1 ]. Building on the theme of frequency generation, Talenti et al. report a dual-nonlinearity approach in AlGaAs microresonators that combines v( 2) and v( 3) processes for efficient microcomb production, enabling flexible on-chip frequency synthesis [ 2 ]. In a more application-driven context, Staels et al. address a well-known limitation of multipass pulse compressors – residual phase distortion – by implementing a pulse-cleaning scheme that restores near-ideal temporal contrast [ 3 ]. The short communication by Glasset et al. contributes a focused study on chaotic dynamics and type-I intermittency in passively Q-switched Tm: YLF lasers, revealing critical thresholds for stable operation in the mid-infrared [ 4 ].
Several papers investigate materials and fabrication techniques that enhance or control light – matter interaction. Bärtschi et al. introduce a multilayer design based on quantized nanolaminates of Ta 2 O 5 and SiO 2, fabricated with precise thickness steps to achieve high reflectivity in the ultraviolet, relevant for advanced mirror coatings [ 5 ]. Divay et al. explore hybrid material integration by coating optical microfibers and nanowires with TiO 2 and PMMA, thereby modifying their nonlinear optical response and opening up routes for integrated fiber-based nonlinear devices [ 6 ]. Belkner et al. propose an integrated system combining laser direct writing and chromatic confocal metrology, which allows for complex, threedimensional structuring on curved surfaces with in-line feedback, a valuable tool for micro-optical prototyping [ 7 ]. Koch et al. investigate the relationship between surface roughness and infrared laser absorption in fused silica components, demonstrating how increased micro-roughness enhances localized heating through multiple internal reflections. Their findings support the development of laser-assisted grinding processes for optical and ceramic materials, highlighting both thermal efficiency and material compatibility [ 8 ].
The theme of optical metrology and resolution enhancement is addressed from both theoretical and practical standpoints. Hüser et al. present a thorough experimental investigation of microsphere-assisted microscopy, assessing resolution gains across different imaging configurations and highlighting practical limits in confocal and interferometric modes [ 9 ]. Nouri et al. offer a broad perspective on dimensional metrology, reviewing a variety of strategies – from digital twins to through-focus scanning – capable of improving measurement fidelity in label-free and structured-light systems [ 10 ]. Dierke et al. quantify the thermal sensitivity of the focal plane in modulation transfer function( MTF) setups, an important contribution for long-term stability in precision imaging [ 11 ]. Scholz et al. revisit the Cat’ s Eye alignment used in asphere
* Corresponding authors: luca. destefano @ na. isasi. cnr. it; rvelotta @ unina. it
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