Third harmonic generation in organic octupole molecules with small absorption at 3ω

The nonlinear optical properties of 1,3,5-tricyano-2,4,6-tri (p-diethylaminostyryl) benzene (TTB) thin films have been measured by using third-harmonic generation (THG) at the fundamental wavelength of 1064 nm. By comparing the THG intensity with that of fused silica, we estimated the third-order electrical susceptibility of the organic film to be 1.2 X10-11 esu, which is about 400 times larger than that of fused silica glass. Due to the unique properties of the TTB films, such as anomalous dispersion and small re-absorption of the third harmonic wave, a thick film is expected to give a more efficient THG, which can be applied to ultrafast optical correlators.