A beam expander lens is a precision optical device designed to increase the diameter of a laser beam, often while maintaining its divergence angle. Its main functions include beam size adjustment, which is crucial for a variety of applications where precise control over the laser's spot size is required. Technological features of a beam expander lens typically include high-quality optical materials that ensure minimal loss of laser power and optimal beam quality. These lenses can come in various configurations, such as Galilean or Keplerian designs, and they are often used in combination with other optical elements. Applications span across industries such as manufacturing, medical, research, and defense, where the beam expander lens plays a vital role in processes like laser cutting, welding, and material processing, as well as in laser-based medical procedures and scientific experiments.