Celso Luis Ladera

Ultrashort-pulse measurement using noninstantaneous nonlinearities: Raman effects in frequency-resolved optical gating

Ultrashort-pulse-characterization techniques generally require instantaneously responding media. We show that this is not the case for frequency-resolved optical gating (FROG). We include, as an example, the noninstantaneous Raman response of fused silica, which can cause errors in the retrieved pulse width of as much as 8% for a 25-fs pulse in polarization-gate FROG. We present a modified pulse-retrieval algorithm that deconvolves such slow effects and use it to retrieve pulses of any width. In experiments with 45-fs pulses this algorithm achieved better convergence and yielded a shorter pulse than previous FROG algorithms.

Direct ultrashort-pulse intensity and phase retrieval by frequency-resolved optical gating and a computational neural network

Ultrashort-laser-pulse retrieval in frequency-resolved optical gating has previously required an iterative algorithm. Here, however, we show that a computational neural network can directly and rapidly recover the intensity and phase of a pulse.

Review of time-frequency domain concepts with application to ultrashort laser pulses

We review the application of time-frequency concepts in the field of ultrashort laser science. We consider the Wigner distribution, the spectrogram, and the sonogram, and show how each of these distributions are used in ultrafast laser science. We also plot four example pulses in each of the three representations.

Retrieving the phase and intensity of an ultrashort pulse using frequency-resolved optical gating and a computational neural network

The method known as frequency-resolved optical gating for the retrieval of the electric field of an ultrashort pulse requires the use of an iterative algorithm. Here we show that using a computational neural network the pulse can be directly recovered.

Recent developments in measuring the intensity and phase of ultrashort laser pulses using frequency-resolved optical gating

Recent developments in frequency-resolved optical gating include an analysis of the iterative algorithms performance in the presence of noise and the development of a direct, rapid retrieval method using a computational neural network.