Large Second-Harmonic Response of C60 Thin Films

Second harmonic generation measurements were performed using 1.064 micro pulses provided by a ND:YAG laser. A bulk second-order susceptibility esu was observed at room temperature, which is about 1.5 times the X2 value of quartz. X2 values in a poling field were studied as a function of temperature; the largest value occurred at a nominal temperature of 140 degC where X2 is ten times larger than the room temperature value.