Ho:YLF (Holmium-doped Lithium Yttrium Fluorides) is a type of laser active crystal that is used for generating laser radiation in the ultraviolet and visible range. This crystal has a high gain coefficient, a broad absorption band and a relatively low thermal lensing effect, which makes it ideal for use in high-power laser systems. The absorption peak of Ho:YLF is centered at 2.1 μm, and it has a wide emission cross-section in the visible and ultraviolet regions, making it suitable for a variety of laser applications, including spectroscopy, industrial processing, and medical and scientific research. Additionally, Ho:YLF is known for its high reliability, long-term stability, and durability, making it a popular choice for laser systems that require long-term performance.