Kashani Ilkhechi Afshin, Martell Matthew, Zemp Roger
Department of Electrical and Computer Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada.
Micromachines (Basel). 2022 Dec 24;14(1):40. doi: 10.3390/mi14010040.
Here, we introduce ultrafast tunable MEMS mirrors consisting of a miniature circular mirrored membrane, which can be electrostatically actuated to change the mirror curvature at unprecedented speeds. The central deflection zone is a close approximation to a parabolic mirror. The device is fabricated with a minimal membrane diameter, but at least double the size of a focused optical spot. The theory and simulations are used to predict maximum relative focal shifts as a function of membrane size and deflection, beam waist, and incident focal position. These devices are demonstrated to enable fast tuning of the focal wavefront of laser beams at ≈MHz tuning rates, two to three orders of magnitude faster than current optical focusing technologies. The fabricated devices have a silicon membrane with a 30-100 μm radius and a 350 nm gap spacing between the top and bottom electrodes. These devices can change the focal position of a tightly focused beam by ≈1 mm at rates up to 4.9 MHz and with response times smaller than 5 μs.
在此，我们介绍了由微型圆形镜面薄膜组成的超快可调谐微机电系统（MEMS）镜，该镜可通过静电驱动以前所未有的速度改变镜面曲率。中央偏转区非常近似于抛物面镜。该器件的制造采用了最小的薄膜直径，但至少是聚焦光斑尺寸的两倍。理论和模拟用于预测最大相对焦移与薄膜尺寸、偏转、束腰和入射焦点位置的函数关系。这些器件被证明能够以约MHz的调谐速率快速调谐激光束的焦波前，比当前的光学聚焦技术快两到三个数量级。制造的器件具有半径为30 - 100μm的硅膜，顶部和底部电极之间的间隙间距为350nm。这些器件能够以高达4.9MHz的速率、小于5μs的响应时间将紧聚焦光束的焦点位置改变约1mm。
