Improved technique to determine second-order optical nonlinearity profiles using two different samples

摘要

An improved inverse Fourier transform Maker fringe (MF) technique is described to retrieve the nonlinearity profile of thin films. It involves measuring the MF curve of two sandwich structures made by combining a pair of different nonlinear samples in two configurations. A simple algorithm is developed to process this data and retrieve the profile of both samples. Compared to our previous technique, which involves a single sandwich structure made of two identical samples, this technique is more flexible, it is insensitive to differences between the samples, and data processing is simpler and much faster. After a sample has been initially characterized by this technique, it can be used as a reference to characterize any other unknown sample using a single MF measurement. Experimental verification is demonstrated with a pair of thermally poled silica wafers.