Optical discs are storage media that use laser technology to read and write data. Common types include CDs, DVDs, and Blu-ray discs. They are typically used for storing music, movies, software, and other digital files. The data is encoded in tiny pits on the disc's surface, which a laser beam can detect. These discs are popular for their portability and durability compared to other storage methods. They can hold varying amounts of data, with CDs storing up to 700 MB, DVDs up to 4.7 GB, and Blu-ray discs up to 25 GB or more. Optical discs are often used in home entertainment systems and computers.