Abstract

The developed apparatus is shown in Fig. 1. AMach-Zehnder interferometer compare the two beams (probe and reference) in amplitude and phase. The sample is located in the probe arm and interacts with the stronger pump beam, orthogonally polarized and collinear to the probe beam. A KLM Ti:sapphire laser (Coherent MIRA 900) was chosen as the source with respect to its unique stability in amplitude and pulse shape. We will report here on time-resolved measurements in which the time delay τ between the pump and the probe pulse gives the basis of this sampling interferometry. We implemented a fringe locking technique to stabilize the phase difference between the probe and the reference beam. An afocal assembly provides a convenient beam waist and controls the phase front to obtain a far field interference pattern free of any fringes.

© 1993 Optical Society of America