Complete pulse characterization: measurements of linear and nonlinear properties

Measurement of the Intensity-Dependent Refractive Index Using Complete Spatio-Temporal Pulse Characterization

“…After performing these calculations we find that the value of the real part of n 2 that allows us to best reproduce the experimental data is Re {n 2 } = 65 × 10 −16 cm 2 /W; this value is in good agreement with other published measurements. [7][8][9] The error associated with this measurement can be estimated as ±10 × 10 −16 cm 2 /W. The comparison of the calculated and measured phases with this value of n 2 is shown in Fig.…”

“…We simulate the propagation of the pulse through the glass using the nonlinear Schrödinger equation and by concentrating on transverse phase variations we extract a value of n 2 consistent with that of previous measurements. [7][8][9] However, we observe that the spectrum of the pulse transmitted through the glass cannot be precisely matched by the solution to the nonlinear Schrödinger equation. This disagreement is not resolved even when we take into account additional effects such as the exact dispersion relation for the material and other plausible nonlinear processes, such as higher-order (n 4 ) nonlinearities, the dependence of the group velocity on intensity, and Raman scattering.…”

“…Here λ is the central wavelength of the pulse, δ the transverse size, τ the duration; I 0 , the peak intensity, for this pulse is equal to 5.5 × 10 9 W/cm 2 and z is the propagation distance; the second-order dispersion, β 2 = 2820 fs 2 /cm, is calculated from Schott's tables 11 and we use an estimate of n 2 ≈ 5 × 10 −15 for the intensity-dependent refractive index, based on previous measurements. [7][8][9] The dispersive and nonlinear phases are comparable and the diffractive phase is negligible. This last fact is confirmed also by the observation that the spatial FWHM of the pulse does not change during propagation; the Rayleigh range for this pulse is in the order of 10 m.…”

Moment-based Description for Assumption-free Single-shot Measurement of Femtosecond Laser Pulse Parameters via Two-photon-induced Photocurrents

“…The pulse duration is usually defined as the FWHM of the assumed pulse intensity as a function of time, which may not always reflect the actual pulse duration. Although there exist also methods like frequency-resolved optical gating [6], frequency domain pulse measurement [7], [8], and the SPIDER technique [9], [10] for complete E-field amplitude and phase recovery, such a detailed description of the femtosecond pulse is usually not mandatory and does not justify the required experimental labor. Further, even if they do not presuppose a temporal form, these latter methods still either assume uniform laser pulses during the data set acquisition or require tedious experimental preparation.…”

Sub femto-joule sensitive single-shot OPA-XFROG and its application in study of white-light supercontinuum generation

“…In the past decade, measuring the intensity and phase vs. time of femtosecond laser pulses has become a great issue due to its application in characterization of ultrafast signal. Basically, there are several families, including direct optical spectral phase measurement (DOSPM) [1], frequency-domain phase measurement (FDPM) [2], frequency-resolved optical gating (FROG) [3,4], and others [5], to characterize the amplitude and phase of electric field profile associated with the optical pulse. Techniques such as Frequency-Resolved Optical Gating (FROG) and Cross-correlation FROG (XFROG) [6,7] allow the measurement of a wide range of pulses.…”