New approach to determine the intensity and phase of ultrashort pulses by use of time-to-space conversion and a noniterative phase-retrieval algorithm

Abstract

We propose a novel scheme for directly determining the intensity and phase of ultrashort pulses. The technique involves time-to-space conversion of an input pulse by a diffraction grating, followed by the detection of its spectral intensity distributions in the Fourier transform plane with and without an exponential filter placed in front of the grating. By use of an efficient noniterative phase-retrieval algorithm, the spectral phase of the pulse is retrieved from these spectral intensities. The intensity and phase of the pulse in the temporal domain can be reconstructed by the inverse Fourier transformation of the retrieved spectral amplitude. Computer simulation results confirm that robust reconstructions of a linearly chirped pulse and a pulse with quadratic and cubic spectral phases are possible with high fidelity.