The Fabrication Method Base On Phase-change Lithography And Optical Properties Of Multiple-bit Optical Pit

And now popular research of ultra-high density optical storage is about the changing in one dimension, such as depth D or angle ?. This paper describes a model of multiple-bit optical disk, which have a lot of depths and angles. For the first time, we proposed the way of using of Stokes parameters to characterize the depths and angles of multiple-bit optical masks, which can increase the optical storage density. The results show that the Stokes parameters can be a good characterization of the multiple-bit optical masks and the S0 and S1 have great relevance of depth and angle. The depth and angle have the same impact to S1, but the depth has a much greater impact of S0 than the angle. Basing on the monotonically increasing range of S0 and S1 about the depth and angle, the depth and angle of multiple-bit marks can be well distinguished. In addition, we introduced the scan pulse width(?W),which can double the angle range bye its different monotonically increasing range of ?W.We can distinguish the range of angle increases to [-90 °, 90 °] using this method. This distinguished range is four times of the angle only by using the detected light intensity. And we design and simulate more multiple-bit data pits based on the previous multiple-bit pit, which are also be established by Stokes parameter signals.In order to achieve the multiple-bit pit patterning, a simply equipped Phase-Change Lithography system was designed. And we successfully verified the feasibility of preparing the multiple-bit pits patterning with the system on Ge2Sb2Te5 amorphous thin film. Furthermore, by making use of the optical properties of Ge2Sb2Te5, an innovative and fast autofocusing method based on the system was proposed. In the experiment, the monolayer amorphous Ge2Sb2Te5 thin film is ill?minated by a laser beam and the minim?m line width can reach to 0.69?m. 1wt% Na OH solution is used to etch laser-induced Ge2Sb2Te5 thin film and the wet-etched multiple-bit pit pattern on Ge2Sb2Te5 thin film is easily recognizable.