光学相干断层扫描成像系统中消偏振分光膜的研制

消偏振分束镜能够将光学相干断层扫描干涉成像系统中的信号光进行分束,是光学相干断层扫描成像系统中重要的组成器件。为了减小45度角入射时P光和S光造成的偏振分离,针对成像系统中分光棱镜的参数要求,选择Ti3O5、Al2O3和Mg F2薄膜材料,借助Macleod膜系设计软件,结合Compact Design功能,运用Optimac和Needle Synthesis两种优化方法进行优化设计,选择电子束加热蒸发和离子源辅助沉积的方式镀制薄膜。根据实际镀膜结果,运用Independent Sensitivity功能对膜层敏感度进行分析,并采用Reverse Engineering模块进行逆向模拟分析,判断镀膜误差主要来源于不同监控波长的光控tooling值有细微的差距以及膜层的Final Swing值过大。通过改变不同监控波长的光控tooling值以及对敏感度较高的膜层进行重点监控,制备的消偏振分光膜经过测试,1310±50nm处P光平均透射比为51.47%,S光平均透射比为49.11%,偏振度为4.59%,满足成像系统的使用要求,并通过了环境测试。

Design and Fabrication of the Non-polarizing Beam Splitter Used in Optical Coherence Tomography Imaging System

Non-polarizing beam splitter is an important component which used in achieves optical coherence tomography Interference imaging system. It is able to split the light beam. In order to reduce the polarization separation between the P polarized light and the S polarized light in the incident angle of 45 degrees, analyses the parameters requirement in the beam splitter of imaging system,choose the Ti3O5,Al2O3 and MgF2 as the film materials,optimize the film de-sign by selecting the appropriate film materials and using Macleod coating design software. Choose electron beam heat-ing evaporation and ion assisted system for the thin film deposition. By using the function of independent sensitivity to analyses the layer sensitivities, and using the Reverse Engineer module simulate the coating result. Combined with the film sensitivities,analyze the causes of the monitoring error,the main error sources is the different tooling factor in dif-ferent wavelength and the unreasonable final swing. By changing the tooling factor in different monitor wavelength and focusing on monitor the high sensitivity layers, the average transmittance of the P polarized light at 1310 ± 50nm is 51.47%, the average transmittance of the S polarized light at 1310 ± 50nm is 49.11%, the polarization is 4.59%. The non-polarizing beam films meet the requirements of the use of optical coherence tomography imaging system, and passed the environmental testing.