本文開發二維複式週期性結構作為波長選擇性放射器，使其在波長6 μm與10 μm處有兩個高於0.4的放射率峰，且各峰值之半高寬皆小於1 μm，可應用在高靈敏氨氣感測系統的開發上。文中使用雙L型結構，藉由調整尺寸來達成目標。研究過程可分為模擬、實驗與近似模型建立三部分:模擬是藉由商用有限元素法軟體COMSOL，進行輻射性質的計算與電磁場的繪製；實驗則是透過奈米金屬轉印將樣本製作出來，再以傅立葉轉換紅外線光譜儀量測其反射率，間接得到吸收率頻譜；最後，建立電感電容模型，成功解釋吸收率峰的激發波長。文中所設計之結構，在30˚斜向入射TE偏振光下，於波長6.6 μm與10.4 μm處各有0.4以上之吸收率峰，且雙峰之半高寬皆小於1 μm，而量測結果，除了吸收波長與模擬結果有2%以內的變動外，吸收峰值與其半高寬皆有達到目標要求。

This work developed a dual-band emitter for high sensitive ammoniacal gas sensing system, which has two emittance peaks at the wavelengths of λ = 6 μm and λ = 10 μm. Each of peaks is more than 0.4 and full width at half maximum of each peak is less than 1μm. The objective of this work is achieved with two L-shape gratings. The process of study can be divided into simulation, experiment and approximate model: the numerical result of spectra and electromagnetic field pattern is simulated by COMSOL which is based on finite element method; the experiment result of the sample of two L-shape gratings is fabricated by nanoimprint lithography, and then obtains the absorptance spectra indirectly by measuring the reflectance spectra with FTIR; finally, the inductor-capacitor circuit model is developed to predict the resonance wavelength of absorption peak at λ = 6.42 μm. The L-shape gratings which is designed in this study can be excited two absorptance peaks at the wavelength of λ = 6.6 μm and λ = 10.4 μm at oblique incidence (θi = 30˚) for TE wave. Each of the peaks is more than 0.4 and the full width at half maximum of each peak is less than 1μm. And the measurement result concerning L-shape gratings is achieved the targets of the peak and the full width at half maximum of peak but the wavelength of absorptance peaks has error within 2 % comparing with the simulation.

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