Free Electron Lasers (FELs) are powerful, tunable sources of coherent electromagnetic radiation, generated by accelerating a beam of electrons through a magnetic structure called an undulator or wiggler, which causes the electrons to emit synchrotron radiation. Unlike conventional lasers, FELs do not rely on a gain medium, allowing them to produce a wide range of wavelengths from microwaves to X-rays, making them invaluable in scientific research and industrial applications.