Wu Shun-Der, Gaylord Thomas K, Glytsis Elias N
School of Electrical and Computer Engineering, Microelectronics Research Center, Georgia Institute of Technology, Atlanta 30332, USA.
Appl Opt. 2006 May 20;45(15):3420-4. doi: 10.1364/ao.45.003420.
The effect of the refractive index of the substrate together with the incident polarization on the optimization of sawtooth surface-relief gratings (SRGs) is investigated. The global optimum diffraction efficiencies of the -1st forward-diffracted order of sawtooth SRGs are 63.3% occurring at n2=1.47 for TE polarization and 73.8% occurring at n2=2.88 for TM polarization. Incident TE polarization has higher optimum diffraction efficiency than TM polarization for all n2<1.85. In contrast, TM polarization has higher optimum diffraction efficiency than TE polarization for all n2>1.85. A polymer (n2=1.5) optimum sawtooth SRG exhibits 62.6% efficiency for TE polarization. A silicon (n2=3.475) optimum sawtooth SRG exhibits 68.6% efficiency for TM polarization. These sawtooth SRGs are compared to right-angle-face trapezoidal SRGs. It is found that the optimum profiles of right-angle-face trapezoidal SRGs have only very slightly increased efficiencies over sawtooth SRGs (0.04% for TE and 0.55% for TM).
研究了衬底折射率和入射偏振对锯齿形表面浮雕光栅（SRG）优化的影响。锯齿形SRG的-1级前向衍射级的全局最佳衍射效率，对于TE偏振，在n2 = 1.47时为63.3%，对于TM偏振，在n2 = 2.88时为73.8%。对于所有n2 < 1.85，入射TE偏振比TM偏振具有更高的最佳衍射效率。相反，对于所有n2 > 1.85，TM偏振比TE偏振具有更高的最佳衍射效率。聚合物（n2 = 1.5）最佳锯齿形SRG对于TE偏振的效率为62.6%。硅（n2 = 3.475）最佳锯齿形SRG对于TM偏振的效率为68.6%。将这些锯齿形SRG与直角面梯形SRG进行了比较。发现直角面梯形SRG的最佳轮廓相比锯齿形SRG的效率仅略有提高（TE偏振提高0.04%，TM偏振提高0.55%）。
