多阶存储是一种无需减小记录波长或增大数值孔径而显著提高光存储容量的新颖方法。对光致变色材料采用不同的光能量写入,读出时则具有不同的吸收率,该特性可用来实现多阶数据存储。在研究光致变色材料曝光特性的基础上,提出了基于光致变色原理的多阶存储数学模型,该模型反映了光致变色材料吸收率与曝光量之间的非线性关系,为光致变色材料的多阶存储写策略的优化提供了理论依据。在4阶和8阶静态存储实验结果中,各信号峰值之间有明显的阶次变化,且信号之间没有交叠现象,从而验证了利用该材料进行多阶存储的可行性。将该多阶技术应用在实际光盘存储中,可实现两至三倍于普通光盘容量的高密度存储。

Multilevel recording, which allows multiple status in each recording pit, is an alternate way to increase the recording density, but need not to directly reduce the spot size by increasing NA (numerical aperture) or reducing λ. The absorption of photochromic material varies with the different optical writing energy, which can be used to realize multilevel data storage. At first, the exposure characteristic of this material as the media of multilevel storage is studied, and the mathematical model of multilevel storage using this material has been achieved. The nonlinear relation between absorption and exposure energy is reflected in the model, which supports to optimize the write strategy of photochromic multilevel data storage. In the results of 4-level and 8-level static multilevel storage experiments, each level of signal amplitude varies obviously without overlap, which proves the possibility of applying this material to multilevel data storage. The capacity of optical disk will be improved by double or treble if this multilevel technology is implemented into practical optical disk storage.