Application of a-C:H Films to Optical Information Recording

用辉光放电分解C_3H_3制备的非晶C：H薄膜在紫外光照射下出现了光刻蚀现象。估计这种光刻的分辨能力足够高，以构建表面浮雕全息图。首次尝试用紫外He-Cd激光直接形成双光束干涉浮雕全息图。用He-Ne激光（633 nm）和Ar^+激光（488 nm）再现的照片图像显示出衍射关系，并给出了全息记录所用光学配置所期望的光栅周期的正确值。为了避免光对全息图记录信息的长期破坏，我们采用了一种标准的方法，即先将原始全息图转换成金属模型，然后在软塑料中对这些模型进行模压加工，以形成全息图的复制品。金属模具是通过在具有原始光学信息作为表面浮雕的蒸镀Au的a-C：H膜上电镀Ni制成的。使用热塑性聚氯乙烯片材成功地复制了原始全息图。该过程具有应用于相同信息的大规模生产的能力。这些复制全息图的衍射效率达到了相应原始全息图的80%，但绝对值不高，反映了原始全息图的低衍射效率。这项研究首次证明，a-C：H薄膜具有仅通过光学曝光可记录的高分辨率光学记录介质的有趣的可能性。

Amorphous C:H films prepared by glow discharge decomposition of C_3H_3 were found to exhibit a photo-etching phenomenon under UV light exposure. The estimated resolving power of this photo-etching is high enough to construct surface relief holograms. Direct formation of two beam interference relief holograms using an UV He-Cd laser has been tried for the first time. The photographed images reconstructed by a He-Ne laser (633 nm) and Ar^+ laser (488 nm) were shown to hold the diffraction relation and to give the correct value of grating period expected for optical configuration used at hologram recording. These results present confirmative evidence that the relief hologram was really constructed in the a-C:H film.In order to avoid long-term deteriorations of recorded information by light, formations of replica holograms were tried with a standard method containing a transforming process of original relief holograms to metal moulds followed by an embossing process of these moulds in soft plastics. The metal moulds were made by Ni- electroplating of Au-evaporated a-C:H films having original optical information as surface reliefs. Successful copies of original holograms were achieved using thermoplastic poly vinyl chloride sheets. This process has a capability of application for mass production of the same information. The diffraction efficiencies of these replica holograms reached up to 80% of that of the corresponding original holograms, though the absolute values were not high, reflecting low diffraction efficiencies of original holograms. This study demonstrated, for the first time, that a-C:H films have an interesting possibility for high resolution optical recording medium being recordable only by optical exposure.