近红外MEMS闪耀光栅的设计与制作

The Design and Fabrication of an NIR-MEMS Blazed Grating

利用硅的各向异性湿法腐蚀性质,在偏晶向(111)硅基底材料上,设计并制作了闪耀角为8°、周期为4μm的近红外闪耀光栅.设计时考虑了光栅顶部平台对光栅衍射效率的影响,修正了光栅的闪耀角.制作时利用一次性氧化削尖的方法,减少光栅顶部平台的宽度,以提高光栅的衍射效率.利用扫描电子显微镜(SEM)进行光栅形貌测试,结果表明:制作的光栅具有平滑的光学表面和良好的光栅槽形.对光栅进行衍射效率测量,当入射波长为1 392nm时,衍射效率能达到70%以上,表明光栅具有很高的衍射效率,能满足微型近红外光谱仪的使用要求.

A near infrared blazed grating with a grating constant of 4 μm and a blazed angle of was designed and fabricated on off-cut silicon （111） wafers. In order to improve the diffraction efficiency of gratings, the blazed angle of the grating was revised and the means of oxidation sharpness was used to cut down the stripes between the grooves of gratings. A scanning electron microscope （SEM） was used to analyze the grating surface. The experimental results showed that the grating samples had good uniformity grooves and grating facets of excellent optical quality. Diffraction efficiency measurement showed that the grating could offer above 70% diffraction efficiency at the wavelength of 1392 nm. It is concluded that the blazed gratings fabricated by this method have high diffraction efficiency and can be used in near infrared micro- spectrometers.