Abstract: A method of generating energetic electromagnetic radiation comprises, during each of a plurality of separated radiation intervals, injecting laser radiation of a given wavelength into an optical cavity that is characterized by a round-trip transit time (RTTT) for radiation of that given wavelength. At least some radiation intervals are defined by one or more optical macropulses, at least one optical macropulse gives rise to an associated circulating optical micropulse that is coherently reinforced by subsequent optical micropulses in the optical macropulse and the electric field amplitude of the circulating optical micropulse at any given position in the cavity reaches a maximum value during the radiation interval.

Abstract: The design and application of an uncoated sapphire crystal as a beamsplitter and output coupler of a laser resonator includes placing the crystal sufficiently close to the Brewster angle to intercept a beam from a lasing medium in a free electron laser to provide a Fox-Smith type resonator or a Michelson type resonator depending on the optical path through the crystal to enable use of high power lasers in interferometric and optical coupling measurements.

Abstract: The present invention provides in a Free electron laser a means to increase the temporal resolution of the optical pulses while simultaneously increasing the spectral resolution of the pulse train. The increase in temporal resolution is achieved by introducing a quadratic temporal phase variation (i.e. linear frequency chirping) across the pulses, and then propagating the outcoupled pulses through a dispersive relay line to compress them to the transform limit of the broadened spectrum.