基于小物镜系统的热像差影响因素分析

光机热集成分析是光机结构设计中的重要环节,对光学系统像质的预测与补偿有着重要的参考价值。针对小物镜系统,进行光机热集成分析,结果表明该系统产生的热像差较大,影响系统光学性能,其中温度升高导致折射率变化引入的系统热像差较大;结构热变形引入的系统热像差较小,可以忽略;镜片与支撑结构之间的导热、上下窗口的空气扰动、机械结构外表面的环境对流也会存在一定影响,但影响较小。由此可知系统热像差的主要影响因素是热载的大小,设计过程中减少透镜厚度及材料吸收率,降低系统热载,是减小光学系统热像差最为有效的途径。     

Charge transport and bipolar switching mechanism in a Cu/HfO_2/Pt resistive switching cell

Bipolar resistance switching characteristics are investigated in Cu/sputtered-HfO_2/Pt structure in the application of resistive random access memory(RRAM).The conduction mechanism of the structure is characterized to be SCLC conduction.The dependence of resistances in both high resistance state(HRS) and low resistance state(LRS) on the temperature and device area are studied.Then,the composition and chemical bonding state of Cu and Hf at Cu/HfO_2 interface region are analyzed by x-ray photoelectron spectroscopy(XPS).Combining the electrical characteristics and the chemical structure at the interface,a model for the resistive switching effect in Cu/HfO_2/Pt stack is proposed.According to this model,the generation and recovery of oxygen vacancies in the HfO_2 film are responsible for the resistance change.     

光纤激光精密位移调整技术实验研究

为了将激光弯曲成形技术应用于精密位移调整领域实现亚微米精度的位移调整,自行设计和搭建了激光微位移调整与测量平台,将光纤激光通过线性透镜和扫描振镜聚焦在不锈钢薄板上作匀速扫描运动,实时监测加工过程样件自由端的输出位移。建立了样件激光微位移调整模型,在此基础上研究改变激光功率、扫描速度、光束照射位置以及离焦量等参数对调整位移的影响。结果表明,样件通过该平台实现了亚微米级重复精度的精密位移调整,改变激光照射位置是精确改变调整位移的首选;通过优化工艺参数,降低了激光加工过程中样件表面的损伤。