Formation of the spontaneous surface relief grating under pulsed exposure

Formation of the spontaneous surface relief grating under pulsed exposure with different pulse widths and repetition rates are studied. We used a low power diode laser with the wavelength of λ= 532nm as pump beam at normal incidence to the surface of azo-polymer film. The wavelength of pump beam is far from the maximum of absorption spectrum. Spontaneous surface relief grating with grating pitch of ~1383nm was formed.