光致聚合物材料中各组分对光聚合速度的影响及其在全息存储中的应用实验

本文研究了光敏剂、光引发剂、光促进剂、单体及高分子成膜树脂等成份对全息光致聚合物薄膜光存储性能的影响.在一定范围内,材料中光引发剂浓度的提高使光聚合速度显著增加,链转移剂浓度则存在一个最佳的相对浓度.适当地增加液态辅助单体含量及其所含双键官能团的数目,会明显增加光聚合速度.在聚醋酸乙烯酯薄膜中单体聚合速度明显优于在醋酸纤维素中的速度,所制备的光致聚合物材料实现了同一位置的多幅全息图像的存储和再现,表明了该材料有用于大容量全息存储的可能.     

Multiple storage of holograms in blocks of PMMA/MMA/Titanocenechloride

101 volume phase holograms are recorded at 514.5 nm by superposition in a 2.6 mm thick block of the polymeric system PMMA/MMA/Titanocenechloride. The sample has been rotated 0.1° between recordings. All volume phase holograms can be read out individually at the corresponding Bragg angles due to the high degree of angular selectivity in a thick storage medium. The holographic recording proceeds irreversibly. Hence a holographic write once — read only memory with very large storage capacity can be realized. The multiple storage capability of this optical recording medium is investigated experimentally.     

绿敏光致聚合物的制备及其光全息存储性能研究

报导了一种新型的对绿光敏感的光致聚合物材料。该材料以丙烯酰胺为单体，由光引发剂，共引发剂，成膜物等组成。本材料记录的全息图衍射效率可达55％。在光聚物上采用角度复用技术存储了10幅图像，得到的再现像信噪比较高。说明该材料适合于大容量体全息存储。     

Vis‐sensitive photopolymer containing vinyl ether compound and pyrromethene dye

A visible light(vis)‐sensitive photoresist based on the concept of chemical amplification was developed utilizing poly(p‐hydroxystyrene) (PHS), 2,2‐bis[4‐(2‐(vinyloxy)‐ethoxy)phenyl]propane (BPA‐DEVE) as a crosslinking agent, N‐trifluoromethylsulfonyloxy‐1,8‐naphthalimide (NIT) as a photoacid generator (PAG) and pyrromethene dyes such as 1,3,5,7,9‐pentamethylbipyrromethene difluoroborate (PRH) and 2,8‐diethyl‐1,3,5,7,9‐pentamethylbipyrromethene difluoroborate (PRE) and 3,3′‐carbonylbis(7,7′‐diethylaminocoumarin) (KCD). On irradiation with an argon ion laser, the photopolymer comprising PRH and PRE exhibited a high sensitivity of 65 and 46 mJ cm^?2, respectively. It is suggested that the sensitization mechanism of the pyrromethene dye/PAG system involves singlet electron transfer. The sensitivity of the photoresist increased with the decreasing molecular weight of PHS because of the high dissolution rate. Copyright © 2002 John Wiley & Sons, Ltd.     

新型防潮的光致聚合物全息记录材料及其应用

本文研制出一种新型兰敏的光致聚合物全息记录材料,并提出再聚会固定全息再现峰值波长的方法.这种记录材料由增感剂,引发剂,链转移剂,单体和成膜物组成.用本材料记录的全息图衍射效率可达95%以上,且能防潮,耐高温.     

基于丙烯酰胺为单体的红敏光致聚合物衍射效率增强的研究

目前以丙烯酰胺为单体的光聚物体系在高分辨力下衍射效率不高。从光聚物聚合机理出发．探讨了其主要原因。从单体聚合难易程度角度提出了加入新成分丙烯酸、使用聚合度低的成膜物、增加膜的厚度和优化凉板时间等四种促进单体聚合的措施并从实验上加以了验证。结果表明：在一定条件下。成膜物使用聚合度为341的聚乙烯醇比聚合度为1750的聚乙烯醇体系衍射效率提高了约60％;加入丙烯酸后衍射效率也提高了10％左右,且使用聚合度低的成膜物和加入丙烯酸后体系更不易结晶;厚度和凉板时间均有一个最佳范围。经过优化实验后得到了空间频率在2000lp／mm时衍射效率大于90％,3000lp／mm时大于55％的结果,且利用制备出的材料拍摄出透射和平面反射全息网,说明该材料适合于日益发展的全息显示。     

In-situ measurement of the surface temperature during holographic recording

Photo-induced processes in organic materials mostly occur on molecular levels. Excited molecules may split to form radicals, starting a polymerization process with diffusing monomers. The azo-dyes perform an optically induced cis-trans isomerization. During pattern formation like a holographic grating, the local temperature increase, especially in thin films, is up to date a subject of estimation from absorption and dissipation data. However, the exact knowledge of the surface temperature would help a lot in understanding the resulting refractive index and thickness patterns during holographic exposure. In this paper, in-situ pyrometer measurements are presented. As examples, different photosensitive materials, varying from a photopolymer to polycrystalline azo dyes, are used in order to outline the magnitude of this effect and demonstrate the feasibility of this technique.     

Analysis of temperature change effects on hologram recordingand a compensation method

For commercialization of holographic storage drives, the effects of temperature changes on holographic medium is critical. There has been no systematic study on the effect of temperature change on hologram recording properties. We believe that the monomer-diffusion speed and polymerization rate changes are critical for hologram-recording properties and estimate those parameters on each temperature using the photopolymer medium process simulation we have developed. We describe how these parameters affect actual recording properties such as sensitivity, M=# and so on. Moreover, we propose a method for compensating temperature changes, and confirm the success of this.     

一种全可见光敏感的光致聚合物全息特性研究

制备了一种对整个可见光波段都敏感的光全息存储材料,并研究了该材料的透过率、衍射效率、灵敏度等全息特性.用He-Ne激光器633 nm和Ar+ 激光器514 nm,488 nm,476 nm四种波长的光曝光,材料的饱和衍射效率最大为66%,最小为48%;最高灵敏度为8.06×10－3 cm2/mJ.最高折射率调制度为4.22×10－4.用多波长存储时,不同波长的光可存储多幅全息图,且再现图像清晰.结果表明,该材料是较好的高密度数字全息存储材料.