one of the most astonishing pieces of scientific equipment that I've ever learned something about is the "free-electron laser", capable of producing ultrashort pulses of light tuned to a desired frequency over an extraordinarily broad range of wavelengths. the hitch is that the amplified light-emission comes from synchrotron radiation, produced by accelerating an electron beam back and forth in a device called a "wiggler" or "undulator". sending charged particles round curved paths at relativistic speeds causes emission of photons tangential to the path; in some fashion obscure to me, doing this over and over again along the length of the wiggler causes laser amplification and coherent emission. it's not exactly benchtop equipment, but its broad tunability and short pulses are exceedingly useful for specialized tasks in molecular spectroscopy.
Also the U.S. military thinks it'd make a spiffy gun. I guess they would. ~Χαρά