Disordered Nanocomposite Islands for Nanospeckle Illumination Microscopy in Wide‐Field Super‐Resolution Imaging

Abstract

Nanospeckle illumination microscopy (NanoSIM) based on disordered metallic nanocomposite island substrates is described. The nanoisland substrates can be fabricated without lithographic techniques. Azimuthal scanning illumination of nanoislands creates near‐field distribution that excites an arbitrary number of basis images to produce super‐resolution. Experimental studies of point‐spread images using NanoSIM with 360 basis images obtained by azimuthal scanning find spatial resolution improved by more than three times with an achievable full‐width‐at‐half‐maximum at 81.1 nm on average. The approach is confirmed by imaging aggregated nanobeads and nanoscale distribution of gangliosides on the HeLa cell membrane.

Label-free detection of single nanoparticles with disordered nanoisland surface plasmon sensor

“…The morphology of the fabricated gold nanoisland film, as found using an atomic force microscope (AFM), is shown in Figure 2(b). Depending on fabrication parameters, the geometrical properties of the random nanoislands follow normal distributions with different size and separations [39,40]. From analysis of Figure 2(b), the size (A), height (H), and nearest separation distance (SD) of the random nanoislands were determined to be A = 0.15±0.074 µm 2 , H = 83±16 nm, and SD = 1.0 ± 0.2 µm.…”

Wide-field nanoscale imaging via near-field speckle illumination by nanoisland substrates

“…This method takes advantage of optical super-resolution imaging capabilities of plasmonic nanostructures, which have gained significant attention in recent years [32][33][34][35][36][37][38][39][40][41][42]. We examined nanospeckle illumination microscopy (NanoSIM) using random distributions of localized plasmonic near-field speckles generated from nanoisland substrates [43]. Our results demonstrate the potential of this technique to improve the resolution and sensitivity of wide-field nanoscale imaging, making it a valuable tool for a broad range of applications.…”

“…The conventional blind-SIM constraint yields the incorrect solution for 𝐼 𝐿 under this non-uniform condition because the sum of all intensity fields is neither constant nor homogeneous. We introduce an approximate homogeneity constraint to circumvent this issue, which allows the intensity 𝐼 𝐿 to be calculated as the average of the two neighboring intensities throughout azimuthal scanning illumination (ASI), i.e., 𝐼 𝐿 ≈ (𝐼 1 + 𝐼 𝐿−1 ) 2 ⁄ [43,45].…”

Label-free detection of single nanoparticles with disordered nanoisland surface plasmon sensor

“…The morphology of the fabricated gold nanoisland film, as found using an atomic force microscope (AFM), is shown in figure 2(b). Depending on fabrication parameters, the geometrical properties of the random nanoislands follow normal distributions with different size and separations [73,74]. Further details of the synthesis and statistics of the nanoisland substrates can be found in [75][76][77].…”