THE NONLINEAR THIRD ORDER DIELECTRIC SUSCEPTIBILITY COEFFICIENTS OF GASES AND OPTICAL THIRD HARMONIC GENERATION

The nonresonant third order nonlinear dielectric susceptibility coefficients of several gases were measured in a four wave mixing experiment. These coefficients were used to calculate the amount of third harmonic radiation generated in gases in a focused laser beam. No signal distinguishable from noise was ever seen from gases, although more than 104 times the minimum detectable signal was predicted.