Kim Sejeong, Kim Hwi-Min, Lee Yong-Hee
Opt Lett. 2015 Nov 15;40(22):5351-4. doi: 10.1364/OL.40.005351.
The miniaturization of optical sensors is essential for the realization of compact, portable, and cost-effective devices. Photonic crystal-based optical sensors, which have an ultra-small mode volume and footprint, have demonstrated remarkable recent progress in achieving a high figure-of-merit (FOM) in a sensor. Here, we report an optical sensor with a high Q-factor and high sensitivity based on a photonic crystal nanobeam using the second lowest air band-edge mode. We calculated that a nanobeam (n=3.4) in a water environment (n=1.33) has refractive-index sensitivity of ~631 nm/RIU, while the quality factor is greater than 23,300. Accordingly, a theoretical FOM of the sensor corresponds to >9500. To the best of our knowledge, experimental refractive-index sensitivity of 461 nm/RIU is the highest value among photonic crystal single nanobeam geometry. The simple geometry of uniform air hole sizes and lattice constants in the proposed nanobeam sensor allows easy fabrication and mechanical stability.
光学传感器的小型化对于实现紧凑、便携且经济高效的设备至关重要。基于光子晶体的光学传感器具有超小的模式体积和占地面积，最近在实现传感器的高优值（FOM）方面取得了显著进展。在此，我们报告一种基于光子晶体纳米光束的具有高Q因子和高灵敏度的光学传感器，该传感器使用第二低的空气带边模式。我们计算得出，在水环境（n = 1.33）中的纳米光束（n = 3.4）具有约631 nm/RIU的折射率灵敏度，而品质因数大于23,300。因此，该传感器的理论FOM大于9500。据我们所知，461 nm/RIU的实验折射率灵敏度是光子晶体单纳米光束几何结构中的最高值。所提出的纳米光束传感器中均匀气孔尺寸和晶格常数的简单几何结构便于制造且具有机械稳定性。
