A femtosecond laser is a type of laser that emits pulses of light lasting just a few femtoseconds, which is one quadrillionth of a second. This incredibly short duration allows the laser to deliver high energy in a very brief time, making it useful for precise applications in various fields, including medicine and materials science. In medical settings, femtosecond lasers are often used in procedures like LASIK eye surgery, where they create precise cuts in the cornea. In research and industry, these lasers can manipulate materials at the molecular level, enabling advancements in nanotechnology and photonics.