The paper is a concise digest of works presented during the 12th National Symposium on Laser Technology (SLT2018) . The Symposium is organized since 1984 every three years [2-11], now every two years. SLT2016 and SLT 2018 were organized by the Institute of Optoelectronics, Military University of Technology (IO, WAT) Warsaw, with cooperation of Warsaw University of Technology (PW), Warsaw University (UW), and Wrocław University of Technology (PWr) in Jastarnia. SLT 2018 was organized on 25-27 September 2018. The Symposium is a representative portrait of the laser technology research in Poland. Symposium Proceedings are traditionally published by SPIE [12-21]. The meeting has gathered around 120 participants who presented around 100 research and technical papers. The Symposium organized now every 2 years is a good representation of laser technology and laser applications development in Poland at university laboratories, governmental institutes, company R&D laboratories, etc. The SLT also presents the current technical projects under realization by the national research, development and industrial teams. Topical tracks of the Symposium, traditionally divided to two large areas – sources and applications, were: laser sources in near and medium infrared, picosecond and femtosecond lasers, optical fiber lasers and amplifiers, semiconductor lasers, high power and high energy lasers and their applications, new materials and components for laser technology, applications of laser technology in measurements, metrology and science, military applications of laser technology, laser applications in environment protection and remote detection of trace substances, laser applications in medicine and biomedical engineering, laser applications in industry, technologies and material science.