Femtosecond lasers are advanced laser systems that emit pulses of light lasting just a few femtoseconds, which is one quadrillionth of a second. These incredibly short pulses allow for precise control over light-matter interactions, making them useful in various applications, including medical surgery, material processing, and scientific research. The unique properties of femtosecond lasers enable them to achieve high-resolution imaging and micro-manufacturing. In ophthalmology, for example, they are used in procedures like LASIK to reshape the cornea with minimal damage to surrounding tissues. Their ability to deliver energy in such brief bursts makes them a powerful tool in modern technology.