光柵耦合表面電漿共振電光調制器之研究

Study on surface plasmon resonance light modulator using a grating coupler

陳孟廷(Meng-Ting Chen)

指導教授 ： 郭文凱

國立虎尾科技大學/電機資訊學院/光電與材料科技研究所/碩士(2010年)

摘要

在論文中，我們利用已商業化EM Explorer和GSolver兩光學模擬軟體進行模擬，其模擬計算值係利用有限差分時域(Finite difference time domain, FDTD)和嚴格耦合波分析(Rigorous coupled wave analysis, RCWA)演算法,為確認軟體計算值是否與理論相符合，分別模擬稜鏡耦合式(Kretschmann configuration)和光柵耦合式(Metal grating structure)，並與菲涅耳(Fresnel)理論計算結果對照，結果發現兩軟體計算結果與理論相符合。之後我們模擬設計兩種光柵耦合式電光調制器，第一種為倒蓋式光柵結構，模擬結果顯示共振角22.98°，半高寬約0.07°，當電光高分子層折射率改變0.0015時造成共振角位移0.06°，將入射角固定在22.98°，外加9.09 V使反射率從4 %變化至69 %，約4.5 V可實現50 %的調制指數；第二種為光柵耦合之長距離表面電漿結構，模擬結果顯示共振角35.81°，半高寬約0.05°，當電光高分子層折射率改變0.0007時造成共振角位移0.06°，將入射角固定在35.81°，外加10.61 V使反射率從1 %變化至60 %，約5 V可實現50 %的調制指數。

關鍵字

表面電漿共振 ； 電光調制器

並列摘要

In this study, we used two commercialized optical simulation software programs, EM Explorer and GSolver, to conduct simulation. Calculations in the simulation were based in a finite difference time domain (FDTD) and using the rigorous coupled wave analysis (RCWA) algorithm. To confirm whether if the calculations performed by the software consisted with the theory, the Kretschmann configuration and metal grating structure were simulated, respectively. The results were then compared with the theoretical calculations of the Fresnel equation. The results showed that the calculated results by the two software programs met with the theory. Further on we simulated and designed two types of grating coupler electro-optic modulators. The first type was an inverse grating structure, where simulation results showed the resonance angle was 22.98°, full width at half maximum (FWHM) was approximately 0.07°. When the refractive index of the EO polymer layer changed to 0.0015, the resonance angular shift was 0.06°. The incident angle was fixed at 22.98°, with an applied 9.09 V to enable the reflectivity change from 4 % to 69 %, which a voltage around 4.5 V can achieve 50% of modulation index; the second was a grating coupler with a long-range surface plasmon structure. Simulation results showed the resonance angle was 35.81°, FWHM approximately 0.05°. When the refractive index of the EO polymer layer changed to 0.0007 the resonance angular shift was 0.06°. The incident angle was fixed at 35.81°, with an applied 10.61 V to enable the reflectivity change from 1% to 60 %, which a voltage around 5 V can achieve 50 % of modulation index.

並列關鍵字

Surface plasmon resonance ； Electro-optic modulator

參考文獻

[1] P.I. Nikitin , A.A. Beloglazov, V.E. Kochergin, M.V. Valeiko, and T.I. Ksenevich, “Surface plasmon resonance interferometry for biological and chemical sensing,” Sensors and Actuators B 54 (1999) pp. 43-50.

[2] A.V. Kabashin, S. Patskovsky, and A.N. Grigorenko, “Phase and amplitude sensitivities in surface plasmon resonance bio and chemical sensing,” Opt. Express, 17(23), (2009) pp. 21191-21204.

[3] H. Raether, Surface Plasmons on Smooth and Rough Surfaces and on Gratings (Springer-Verlag, 1988).

[4] G. T. Sincerbox and J. C. Gordon II, “Small fast large-aperture light modulator using attenuated total reflection,” Appl. Opt. 20(8), (1981) pp. 1491-1493.

[5] J. Schildkraut, “Long-range surface plasmon electro-optic modulator,” Appl. Opt. 27(21), (1988) pp. 4587-4590.