Photoinduced surface relief grating (SRG) formation for a single crystal of 4-aminoazobenzene was investigated. It was found that SRG could be inscribed on the (001) surface of the crystal, which might suggest that the photoinduced SRG formation is a general phenomenon observed for single crystals of azobenzene-based molecules as well as for azobenzene-based amorphous systems. In addition, the dependences of the SRG formation upon the orientation of the sample crystal and upon the polarization of the writing beams were found to be different from those observed for previously reported crystalline systems.
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Since the optical density for polarized light with polarization direction parallel to the b-axis was somewhat larger than that parallel to the a-axis, the b-axis was selected as a primary axis for determining H and V orientations of the sample crystal according to the previous works of SRG formation using single crystals [30–33].
