Ultra-broadband IR continuum generation and its phase measurement using cross-correlation FROG

Summary form only given. Ultrashort laser pulse technology plays an important role in the fields of physics, chemistry, biology, etc. The shorter the pulse, the faster the time scales that become accessible. More importantly, the broad bandwidths of such pulses, whether the pulses are short or not, are useful for many applications, including communication, coherent control of chemical reactions, ultrahigh-spatial-resolution optical coherence tomography, and optical metrology. Various approaches have been used to generate such broadband light, and continuum generation has been particularly successful, currently holding the record for the shortest event ever created in the visible-near IR spectral region (Baltuska et al, IEEE J. Quant. Electron., vol. 35, pp. 459-478, 1999). In this paper, we report fairly flat-spectrum ultra-broadband IR continuum generation extending from 880 to 2400 nm using a high-energy 1550 nm pulse from a fiber oscillator/amplifier system (Galvanauskas et al, Opt. Lett., vol. 22, pp. 105-107, 1997), coupled into a standard fiber for continuum generation. Using cross-correlation frequency-resolved optical gating (XFROG) with an angle-dithered nonlinear crystal, we measured the continuum intensity and phase.