Camera detection and modal fingerprinting of photonic crystal nanobeam resonances

Abstract

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.

Refractometric Imaging and Biodetection Empowered by Nanophotonics

“…In recent years, out-of-plane elastic scattering signals generated from planar waveguiding devices at the far field have been explored so as to understand the unique "fingerprint" for identifying resonance signals [185][186][187] or spectral changes. [188] Elastic light scattering microscopy using coupled microring resonators, also known as "coupled-resonator optical waveguide (CROW)," acts as an efficient label-free sensing scheme operating in the spatial domain in a spectrometer-free way (Figure 14a).…”

Synthesis of poly(styrene-N-hydroxymethyl acrylamide) microspheres and their application in patterned photonic crystals

“…are all typical structural colors. 10–12 Compared with pigment colors, structural colors usually exhibit high saturation, high brightness and lifelike characteristics. In recent years, structural colors have been widely used in display, sensing, textile, detection and other fields.…”