A new method for the determination of spatially resolved phase differences of nonlinear susceptibilities is presented. The technique is based on the interference of the signal field with a reference field. A phase-shifting element that directly changes the phase difference between the two second-harmonic fields is introduced. The reliability of the method is tested by an experiment with two quartz crystals. As a first application, a measurement of the phase difference between domains in antiferromagnetic YMnO<sub>3</sub> is presented.
© 1999 Optical Society of America
St. Leute, Th. Lottermoser, and D. Fröhlich, "Nonlinear spatially resolved phase spectroscopy," Opt. Lett. 24, 1520-1522 (1999)