A time-resolved pump-probe system to study the dynamic excited-state nonlinearities of chloroaluminum phthalocyanine/ethanol solution based on the 4f nonlinear-imaging technique with a phase object

The 4f nonlinear-imaging technique with a phase object (NIT-PO) is a new method to measure the optical nonlinearity of materials by a single laser shot. A time-resolved pump-probe system based on this technique is constructed by introducing a pump beam with variable temporal delay, which can simultaneously measure the dynamic nonlinear absorption and refraction conveniently. Based on this system, we study the dynamic excited-state nonlinearities of the chloroaluminum phthalocyanine (CAP)/ethanol solution. Dynamic absorption coefficient and refractive index are deduced through analyzing frames of nonlinear image with different time delays from the standpoint of energy and the standpoint of information, and some photophysical parameters of the CAP are sequentially validated by theoretically fitting the experimental curves. On the other side it is demonstrated that the pump-probe system based on 4f NIT-PO plays a responsible role in simultaneously measuring the dynamic nonlinear absorption and refraction of materials, and the system could be a good tool for notarizing and characterizing the origins of optical nonlinearities within materials.