Afzal Francis O, Petrin Joshua M, Weiss Sharon M
Opt Express. 2019 May 13;27(10):14623-14634. doi: 10.1364/OE.27.014623.
We demonstrate in simulation and experiment that the out-of-plane, far-field scattering profile of resonance modes in photonic crystal nanobeam (PCN) cavities can be used to identify resonance mode order. Through detection of resonantly scattered light with an infrared camera, the overlap between optical resonance modes and the leaky region of k-space can be measured experimentally. Mode order dependent overlap with the leaky region enables usage of resonance scattering as a "fingerprint" by which resonant modes in nanophotonic structures can be identified via detection in the far-field. By selectively observing emission near the PCN cavity region, the resonant scattering profile of the device can be spatially isolated and the signal noise introduced by other elements in the transmission line can be significantly reduced, consequently improving the signal to noise ratio (SNR) of resonance detection. This work demonstrates an increase in SNR of ∼ 19 dB in out-of-plane scattering measurements over in-plane transmission measurements. The capabilities demonstrated here may be applied to improve characterization across nanophotonic devices with mode-dependent spatial field profiles and enhance the utility of these devices across a variety of applications.
我们通过模拟和实验证明，光子晶体纳米光束（PCN）腔中谐振模式的面外远场散射轮廓可用于识别谐振模式阶数。通过用红外相机检测共振散射光，可以通过实验测量光学共振模式与k空间泄漏区域之间的重叠。与泄漏区域的模式阶数相关重叠使得共振散射能够用作“指纹”，通过该“指纹”可以通过远场检测来识别纳米光子结构中的共振模式。通过选择性地观察PCN腔区域附近的发射，可以在空间上隔离器件的共振散射轮廓，并显著降低传输线中其他元件引入的信号噪声，从而提高共振检测的信噪比（SNR）。这项工作表明，面外散射测量中的SNR比面内传输测量提高了约19 dB。这里展示的能力可用于改善对具有模式相关空间场分布的纳米光子器件的表征，并增强这些器件在各种应用中的实用性。
