Abstract

For various applications in nonlinear optics and strong field-matter interactions pulses as short and intense as possible are required. The prerequisites of a short pulse duration are a broad spectrum and a chirp-free spectral phase (i.e. group delay dispersion, <GDD>=0). Recently, very efficient methods for spectral broadening have been developed, enabling the generation of a continuum stretching from the visible to the near infrared (500-950nm). This huge spectral width corresponds to a pulse duration of less than 3fs under the assumption of a bandwidth-limited pulse (GDD=0). In order to approach this limit, the positive GDD introduced by the spectral broadening mechanism and the beam manipulation has to be compensated. For high peak powers this compensation must be introduced by reflecting optical components that provide both high reflectance and the prescribed dispersion over the broadest possible bandwidth. This is one of the challenging problems solved by the chirped mirror design algorithm we present here. The mirrors we have produced exhibit high reflectance and constant negative dispersion over the bandwidth 600-950nm (the broadest ever demonstrated, to our knowledge), and have been capable of supporting the generation pulses as short as 4fs [1].

© 1998 Optical Society of America