Femtosecond Waveform Processing via Spectral Holography

Compared to the advanced technology now available for generating femtosecond optical pulses, the ability to manipulate and process ultrashort pulses is still rather primitive. Recently, a number of techniques for shaping and synthesizing femtosecond pulse waveforms have been developed.1,2 These techniques rely on linear filtering of the individual optical frequency components contained within an ultrashort pulse. Although these techniques can be very effective, certain basic signal processing operations, such as time reversal, correlation, and convolution, cannot be achieved by linear filtering. In this paper we discuss the use of spectral holography to perform storage, recall, and nonlinear filtering of shaped femtosecond pulses. In particular, we demonstrate time-reversal, correlation, and convolution of femtosecond optical waveforms.