Femtosecond dispersion compensation with multilayer coatings: toward the optical octave

Dispersive multilayer coatings have found widespread use, particularly in the compensation of material dispersion in femtosecond oscillators and amplifiers. Other than prism or grating sequences, only chirped mirrors allow for the compensation of a much more general spectral dependence of the dispersion. The current state of the art in ultrabroadband mirror design for dispersion compensation is reviewed. Approaches to expand the utility of chirped-mirror coatings toward the coverage of an even-wider bandwidth beyond the optical octave are discussed.