Advanced Solid-State Lasers 2025: feature issue introduction

This joint feature issue of Optics Express and Optical Materials Express presents 38 peer-reviewed articles associated with the Advanced Solid-State Lasers 2025 conference, held as part of the Optica Laser Congress in Prague, Czechia, from 19 to 23 October 2025. The collection reflects continuing progress in solid-state laser materials, laser architectures, ultrafast and high-power sources, nonlinear optics, and frequency conversion. The contributions span rare-earth and transition-metal-doped crystals, ceramics, glasses, and fibers; nonlinear materials; laser operation from continuous-wave to pulsed and ultrafast regimes; and spectral coverage from the visible to the mid-infrared. Together, the articles demonstrate advances in nonlinear and gain-media engineering, thermal management, pulse control, frequency conversion, and source scalability, while addressing applications in spectroscopy, sensing, communications, remote sensing, and medicine.