ALTERNATIVE INTERPRETATION OF IMPULSE-RESPONSE OF PHONON-POLARITONS

A new technique to deal with the time-resolved data, without referring to a dispersion relation, is proposed for an optical grating experime nt on an electrooptic medium. The fundamental concept behind this appr oach is a simple relation among macroscopic and measurable quantities. General features concerning the behavior of the observable are formul ated, same of which have been overlooked in the past studies. The most important characteristic is that the index changes measured at three different spatial frequencies are sufficicient for determining the die lectric and electrooptic properties of the medium. Possible approximat ions in the present approach are discussed in connection with the resu lts of the previous time-resolved studies on LiTaO3.