Tunable-laser-induced gratings for the measurement of ultrafast phenomena

Optically induced gratings form the basis of a class of optical frequency-domain techniques for the measurement of ultrafast phenomena with demonstrated temporal resolution on the order of tens of femtoseconds without the use of ultrashort pulses. We describe these techniques and calculate experimental line shapes. We discuss experimental strategies and some experimental problems that have plagued early experiments, but which have been solved. In addition, we present results obtained for triphenyl methane dyes and the optical Kerr liquid, carbon disulfide, and we discuss the interpretation of these results.