A tunable laser is a type of laser that can emit light at different wavelengths or frequencies. This allows for precise control over the output of the laser, making it versatile for a wide range of applications in fields such as telecommunications, spectroscopy, and medical imaging. Tunable lasers can be adjusted to emit specific wavelengths of light by changing the properties of the laser cavity or the optical gain medium. This enables researchers to tailor the laser output to meet the requirements of their experiments or applications, making tunable lasers a valuable tool in scientific research and technology development.