Nonlinear Optical Properties And Ultrafast Dynamics Of Phthalocyanine

While reaching quantum optics, modern optics produces many new subjects. The nonlinear optics is a new branch of modern optics. In particular, the advent and development of laser provides a powerful tool for perfection of the nonlinear optics. Nonlinear optics promotes the innovation of the laser, and realizes its development from the static optics to transient optics and macro optics to micro optics. Nonlinear opticas investigates materials through many aspects of investigation and operation observation in terms of space size, such as in the micron level and even in molecular, atomic size. The researches on the physical mechanism and the process of materials transformation have moved from nanosecond, picosecond and even reached the femtosecond, attosecond. In view of this, we mainly investigate nonlinear optical properties and ultrafast excited state dynamics features of phenoxy-phthalocyanine and metal phthalocyanine compounds by using multiphoton absorption characteristics, the Z-scan technique, absorption spectra, fluorescence detection technology and so on. Phthalocyanine has a series of multiphoton absorption characteristics. We analyzed the all-optical switching and optical limiting properties of phenoxy-phthalocyanines. The effect on materials’ dynamics characteristics of excited state are analyzed by comparing the experimental measured results of phenoxy-phthalocyanines.Firstly, the development of measurement methods of the material nonlinear optical properties is comprehensive analysed, and the advantages and disadvantages of various methods are introduced. At the same time, we give a brief overview of the development of Z-scan technique, and derive the basic theory of gaussian decomposition method and diffraction theory. The sensitivity and influence factors of Z-scan technique are explored. We also enhance the measuring sensitivity of elliptical beam Z-scan technology based on two-dimensional binary diffraction imaging principle. Finally, we make the numerical analysis based on Fourier transform and huygens-fresnel diffraction principle theory and optimize the measurement technology.Secondly, for a series of 2, 9, 16, 23-4 phenoxy-phthalocyanine compounds synthetized through greenhouse coordination method in our research group recently, and Fe Pz supplied by chemical academy of HIT, the corresponding multi-photon absorption coefficient are studied through nano-second and femto-second Z-scan technology. Five-level and four-level models are built to analyze the nonlinear optical characteristics in the two cases above, respectively. The results show that the nonlinear absorption stems from the contributions of the first excited state of triplet state and the highly excited state of singlet state. Furthermore, the nonlinear property of zinc phenoxy-phthalocyanine is better than hydrogen phenoxy- phthalocyanine solution, which is better than that of ferrocene solution.Thirdly, we analyze the all-optical switching characteristics, light intensity modulation characteristics and optical limiting characteristics of these organic compounds by the nanosecond pump-probe technology and transmission absorption technology and give the corresponding theoretical explanation. The concrete analysis shows that all-optical switching response time of C60 toluene solution is faster than that in the phthalocyanine solution under the action of nanosecond laser, but the all-optical modulation characteristics of the phthalocyanine solution is better than that of C60 toluene solution. The thesis also reveals that the optical limiting properties of the metal-phthalocyanine are superior to that of the metal-free phthalocyanine.Finally, the fluorescence spectroscopy and excited state dynamics properties of phthalocyanine are experimentally studied by fluorescence detection technology and ultrafast(femtosecond pulses) pump-probe technology. The corresponding fluorescence spectra properties of single-photon and two-photon are analysed. The excited state relaxation process is characterized. Furthermore, the physical mechanism of ultrafast laser effect is analysed by energy level transition diagram. The results show that the rapid relaxation due to the intramolecular vibrational relaxation, and a slower relaxation from the internal conversion of energy levels.