摘要
基于严格耦合波分析理论,将嵌入式光栅多层结构平面衍射的理论模型扩展至锥形衍射的情况,可以模拟具有任意波长、偏振态、方位角和入射角的平面波入射该多层结构后形成的衍射。在此基础上,研究了微机械声光传感器锥形衍射中+1级光衍射效率的收敛性。仿真表明:TM(Transverse Magnetic)偏振光入射且光栅周期为4μm时,当谐波数M(2n+1)分别为67、69、71时,+1级光衍射效率分别为28.86%、28.84%、28.86%,收敛性较好。另外,优化了微机械声光传感器的位移灵敏度,当入射角为22°、方位角为10°、光栅周期为1μm时,与周期为4μm的+1级衍射光相比,TE、TM偏振光入射时0、+1级衍射光的位移灵敏度均提高一倍,可以准确地监测该传感器中声压或驱动电压引起的金属膜的位移。
Based on rigorous coupled wave analysis, the models for grating-embedded multilayer structure planar diffraction were generalized to the case of conical diffraction. The proposed method can be used to calculate the light diffracted from the grating-embedded multilayer structure with arbitrary wavelength, polarization, azimuthal angle and incident angle. For the micromachined optoacoustic sensor, the convergence performance of the diffraction efficiencies of the reflected ＋lst order in conical diffraction was investigated. The simulations show that using a 4 μm grating period and TM （Transverse Magnetic） polarization, when the numbers of harmonics M （2n＋1） are 67, 69 and 71, the diffraction efficiencies of the ＋lst order are 28.86%, 28.84% and 28.86%, respectively. Then the displacement sensitivity of the micromachined optoacoustic sensor was optimized. When the incident angle, the azimuthal angle and the grating period are 22°, 10° and 1 μm, respectively, compared with the ＋lst diffracted orders of 4 μm grating period, the displacement sensitivity of the 0th and ＋1st orders under TE and TM polarization was nearly doubled. It can be used to accurately monitor the metal membrane displacement induced by the acoustic pressure or electrostatic actuation voltage.
出处
《红外与激光工程》
EI
CSCD
北大核心
2014年第6期1899-1904,共6页
Infrared and Laser Engineering
基金
国家自然科学基金重点项目
国家中长期科技重大专项(F050809/60938003)
关键词
严格耦合波法
亚波长光栅
多层结构
锥形衍射
rigorous coupled wave analysis
sub-wavelength grating
multilayer structure
conical diffraction
