3RD-ORDER OPTICAL NONLINEARITY AND ALL-OPTICAL SWITCHING IN POROUS SILICON

The third-order optical nonlinearity ((3)(chi)) of porous silicon has been measured using the Z-scan technique. Intensity dependent absorpti on was observed and attributed to a resonant two photon absorption pro cess. The real and imaginary parts of ((3)(chi)) have been measured at 665 nm and found to be 7.5x10(-9) esu and -1.9x10(-9) esu, respective ly. This constitutes a significant esu enhancement over crystalline si licon, All optical switching based on nonlinear absorption is demonstr ated. (C) 1995 American Institute of Physics.