Research On The Measurement Of Nonlinear Optical Property Of Polymer Based On Attenuated-Total-Reflection Technique

During the high-speed and large-capacity information processing, photonic technology and photonic materials have developed rapidly. In recent years, optical fiber communication, optical signal processing and optical computing have greatly promoted the development of nonlinear optical (NLO) materials research and applications. NLO polymers have received increasing attention because of their fast response time and large second order?third order optical susceptibilities. They have advantages of synthesis and processing compared with other NLO materials. They have good mechanical properties and high laser damage threshold. The cost of the production of the NLO polymers are low, and thus the polymer NLO materials has made very encouraging progress over the past decade.The research and the measurement of the interaction between photons and NLO polymers are the theoretic basis for developing NLO photonic devices. Efficiently characterizing the nonlinear optical parameters of the NLO polymeric photonic devices is also very important to optimize the molecular design of functional photonic devices.In an Attenuated-Total-Internal-Reflection (ATR) multi-layer structure, light reflectivity can be strongly dependent on layer parameters such as the layer thickness and refractive index. A tiny variation of these parameters can lead to a large change in the light reflectivity. This characteristic enables the realization of many novel type optoelectronic devices based on this structure. Therefore, we can measure the electro-optic coefficients of the polymeric waveguide by using the ATR technique. In this dissertation, we have proposed a method to measure the NLO properties of the NLO polymer based on the ATR technique: the linear and quadratic electro-optic coefficients of the NLO polymer are simultaneously obtained based on the ATR technique; by using the technique of the attenuated-total-reflection, the complex second hyperpolarizability for quadratic electro-optic effect of linear conjugated polymer is determined at the wavelength of the absorption edge by employing the data measured from different guided wave resonance dips; the?( -?4 ;?3 ,?2 ,?1)is obtained after the frequency-independent component of the?( -?4 ;?3 ,?2 ,?1)is given by doing a least-square fit to the data of?( -?;0,0,?) for the quadratic electro-optic effect.We accomplished the measurement of the NLO parameters by using semi-conductor laser instead of high power pulse laser, the lock-in amplifying technique is no longer needed, and only one single optical path is employed, leading to the simplification of the experimental setup, which offers a rapid, sensitive approach to characterize the polymer with NLO effects.