Time-resolved pump-probe system based on a nonlinear imaging technique with phase object

Abstract

A nonlinear imaging technique with phase object, which can deduce nonlinear absorption and refraction coefficients by single laser-shot exposure, is expanded to a time-resolved pump-probe system by introducing a pump beam with a variable temporal delay. This new system, in which both degenerate and nondegenerate pump and probe beams in any polarization states can be used, can simultaneously measure dynamic nonlinear absorption and refraction conveniently. In addition, the sensitivity of this new pump-probe system is more than twice that of the Z-scan-based system. The semiconductor ZnSe is used to demonstrate this system.

Excited state refraction of C 70 /toluene studied by using 4 f coherent imaging system with phase object

“…As mentioned in Ref. [12], the ratio ω e /ω p (ω e is the radius of the pump beam and ω p is the radius of the probe beam) plays an important role in determining the sensitivity of the measurement. The best choice of this ratio is about 2-3.…”

Investigation of nonlinear refraction of the C60/toluene solution by a time-resolved pump-probe system based on a 4fnonlinear imaging technique with the phase object

“…The experimental arrangement for the time-resolved pumpprobe system based on a 4f NIT-PO as shown in figure 1 is similar to that used in the previous work [16][17][18]. We do not repeat unnecessary details concerning the description of the experiment here.…”

“…The traditional time-resolved pump-probe technique is used mostly for the study of the dynamics associated with absorptive nonlinearities that generally give rise to strong signals [14]. A newly modified system incorporating a 4f NIT-PO [15] with a time-delayed pump-probe technique has been shown to exhibit greater signal sensibility [16] and can simultaneously measure the dynamic nonlinear absorption and refraction conveniently. More important is the technique's capability of simultaneously extracting information on both the magnitude and the sign of the optical nonlinear coefficients, as well as the dynamics associated with energy states and motion of the molecule.…”

Field-free molecular alignment detection by 4f coherent imaging

“…In the latter, the phase shifting filter and the unknown phase object are located at the Fourier and input plane of a 4f imager system, respectively. In the former, the filter is placed at the input plane of the imager in order to get information about the field-induced nonlinear phase produced at the Fourier plane of the imager, as originally proposed by Boudebs et al [10] and recently implemented in a pump-probe version [11].…”