A method for reverse design of the resonance-domain rectangular-groove dielectric grating based on modal method is presented. The design of the polarization (non-polarization) beam splitter and blazed grating is discussed. As an example, the — 1st transmitted order blazed grating with fused-silica is designed with the reverse design method. The basic idea behind the method is the excitation and propagation of the propagating modes in gratings. As different phase difference is accumulated for the first two propagating modes excited in gratings, the incident light can be diffracted into the —1st or Oth order with about 100% diffraction efficiency for TE or TM polarization. The diffraction efficiency of the —1st transmitted order blazed grating is calculated with the rigorous couple-wave analysis (RCWA) method. The geometrical parameters of the blazed grating calculated by the modal method agree well with the results simulated by RCWA.%采用模态法研究了共振域光栅分束器及闪耀光栅等光学器件的设计原理及逆向设计方法,给出了-1级非偏振闪耀光栅的典型设计示例.研究表明,自准直角入射时,光束在光栅内传输将激发产生离散模,通过调节离散模透过光栅传输时的累积相位差,可对衍射光进行调控,实现偏振(非偏振)分束、偏振(非偏振)闪耀等功能.采用严格耦合波法对基于模态法逆向设计的-1级非偏振石英闪耀光栅的几何参数进行验证,计算结果显示两者非常吻合,证明了该方法的正确性.
展开▼
