Two-dimensional observation of the Maker fringe and its application to the poling state evaluation of ferroelectric domains

Two-dimensional images of the Maker fringe have been successfully obtained with a second-harmonic generation microscope that we recently constructed. Compared with conventional Maker fringe methods, our experimental technique offers several advantages of direct and rapid calculation of coherence lengths of optical nonlinear crystals. In addition, owing to the sensitivity of second-harmonic waves to orientational inhomogeneities, two-dimensional images built by second-harmonic waves make it possible to observe and evaluate the poling state of ferroelectric single domains or inhomogeneities in a specimen. Key words: Second-harmonic generation microscope, Maker fringe, ferroelectric domain, LiNb[O.sub.3].