Ultrafast nonlinear refraction in integrated Fabry-Perot etalon containing polydiacetylene

A nonlinear integrated Fabry-Perot etalon containing poly-1,6-dicarbazolyl-2,4-hexadiyne (poly-DCHD) nanocrystals has been fabricated. Time-resolved fringe shifts following picosecond excitation at 645 nm are monitored with a broadband white-light-continuum probe. The shift towards shorter wavelengths indicates a negative refractive index change. The magnitude of the refractive cross-section is found to be 1.6/spl times/10/sup -21/ cm/sup 3/, at a wavelength of /spl sim/700 nm, suggesting that polydiacetylene nanocrystal thin films are well suited for Fabry-Perot based all-optical switching devices.