摘要
利用亚波长孔径光纤点衍射可同时得到大数值孔径和高亮度的点衍射球面波前,进而解决了针孔点衍射和单模光纤点衍射中分别存在的点衍射波前能量微弱和最大孔径角小的不足。基于矢量衍射理论的时域有限差分(FDTD)方法对点衍射球面波前质量进行仿真分析,研究了亚波长孔径光纤的孔径、锥角、镀膜厚度、数值孔径范围等因素对点衍射波前误差、最大孔径角、能量透射率和强度分布均匀性的影响。仿真结果表明,当亚波长光纤孔径为0.5μm,点衍射波前最大孔径角超过90°,能量透射率大于29%,对应数值孔径为0.60的点衍射波前误差均方根(RMS)值优于0.0011λ。仿真结果验证了用亚波长孔径光纤点衍射实现大数值孔径和高亮度的点衍射球面波前的可行性,并为实际系统中亚波长孔径光纤的相关参数的选择提供了精确的数值依据。
Based on the fiber with sub-wavelength aperture, the point-diffraction wavefront with both high numerical aperture （NA） and high power is obtained, by which the poor light power of pinhole point diffraction wavefront and the small aperture angle of single-mode fiber point diffraction wavefront can be solved. We analyze the point-diffraction wavefront based on the finite difference time domain （FDTD） method, and the effects of various factors such as aperture, cone angle, film thickness of sub-wavelength-aperture fiber and NA on point- diffraction wavefront error, aperture angle, light transmittance and intensity uniformity are discussed in detail. The simulation results show that an aperture angle about 90° and light transmittance about 2996 can be obtained with 0.5 μm sub-wavelength fiber aperture, and the corresponding testing precision is better than root mean square value 0.0011λ within 0.60 NA. The simulation demonstrates the feasibility of high NA and high power of point-diffraction wavefront, and provides theoretical basis for choosing the dimension of sub-wavelength-aperture fiber in practical system design.
出处
《光学学报》
EI
CAS
CSCD
北大核心
2015年第9期159-167,共9页
Acta Optica Sinica
基金
国家自然科学基金(11404312
51375467
61205082)
国家重大科学仪器设备开发专项(2011YQ03011208)
浙江省自然科学基金(LQ13F050002)
浙江省“仪器科学与技术”重中之重学科开放基金(JL150508)
广西高校光电信息处理重点实验开放基金(KFJJ2014-03)
广西自动检测技术与仪器重点实验开放基金(YQ15204,YQ14206)
广西自然科学基金(2013GXNSFDA019002,2014GXNSFGA118003)
关键词
测量
点衍射
亚波长孔径光纤
波前质量
时域有限差分
measurement
point-diffraction interferometry
sub-wavelength-aperture fiber
wavefront quality
finite difference time domain
