Opt Lett. 2015 Aug 1;40(15):3504-7. doi: 10.1364/OL.40.003504.
Photonic crystal split-beam nanocavities allow for ultra-sensitive optomechanical transductions but are degraded due to their relatively low optical quality factors. We have proposed and experimentally demonstrated a new type of one-dimensional photonic crystal split-beam nanocavity optimized for an ultra-high optical-quality factor. The design is based on the combination of the deterministic method and hill-climbing algorithm. The latter is the simplest and most straightforward method of the local search algorithm that provides the local maximum of the chosen quality factors. This split-beam nanocavity is made up of two mechanical uncoupled cantilever beams with Bragg mirrors patterned onto it and separated by a 75-nm air gap. Experimental results emphasize that the quality factor of the second-order TE mode can be as high as 1.99×10(4). Additionally, one beam of the device is actuated in the lateral direction with the aid of a NEMS actuator, and the quality factor maintains quite well even if there is a lateral offset up to 64 nm. Potentially promising applications, such as sensitive optomechanical torque sensor, local tuning of Fano resonance, all-optical-reconfigurable filters, etc., are foreseen.
光子晶体分束纳米腔可实现超灵敏的光机械转换，但由于其光学品质因数相对较低而受到影响。我们提出并实验证明了一种新型一维光子晶体分束纳米腔，该纳米腔优化了超高光学品质因数。该设计基于确定性方法和爬山算法的结合。后者是局部搜索算法中最简单、最直接的方法，可提供所选品质因数的局部最大值。该分束纳米腔由两个机械解耦的悬臂梁组成，梁上带有布拉格反射镜，通过 75nm 的气隙隔开。实验结果表明，二阶 TE 模式的品质因数可高达 1.99×10(4)。此外，该器件的一个梁在 NEMS 致动器的辅助下沿横向方向被致动，即使存在高达 64nm 的横向偏移，其品质因数也能保持得相当好。可以预见，这种器件有望应用于敏感的光机械扭矩传感器、法诺共振的局部调谐、全光可重构滤波器等领域。
