For reproducing sound, a CD (Compact Disc) audio player uses a

A Compact Disc is an optical storage medium read by an optical pickup that uses a focused laser beam to scan the spiral track of pits and lands; low-power solid-state laser diodes and precision optics form the front end of CD players [1]. Historical and technical descriptions of optical-disc systems describe the laser beam being focused through an objective lens onto the information layer (e.g., a 1 mW He–Ne laser for early optical systems) and the reflected light being converted into the digital signal stream. Detailed treatments of CD mechanisms (focus/tracking and readout) also emphasize optical laser pickup designs rather than mechanical needles or piezo ceramics.

Sources

1. [1] https://www.repairfaq.org/REPAIR/F_cdfaq1.html