Super-Resolution Imaging at Mid-Infrared Waveband in Graphene-nanocavity formed on meta-surface

Abstract

Plasmonic structured illumination microscopy (PSIM) is one of the promising wide filed optical imaging methods, which takes advantage of the surface plasmons to break the optical diffraction limit and thus to achieve a super-resolution optical image. To further improve the imaging resolution of PSIM, we propose in this work a so called graphene nanocavity on meta-surface structure (GNMS) to excite graphene surface plasmons with a deep sub-wavelength at mid-infrared waveband. It is found that surface plasmonic interference pattern with a period of around 52 nm can be achieved in graphene nanocavity formed on structured meta-surface for a 7 μm wavelength incident light. Moreover, the periodic plasmonic interference pattern can be tuned by simply changing the nanostructures fabricated on meta-surface for different application purposes. At last, the proposed GNMS structure is applied for super-resolution imaging in PSIM and it is found that an imaging resolution of 26 nm can be achieved, which is nearly 100 folds higher than that can be achieved by conventional epi-fluorescence microscopy. In comparison with visible waveband, mid-infrared is more gently and safe to biological cells and thus this work opens the new possibility for optical super-resolution imaging at mid-infrared waveband for biological research field.

Super-Resolution Imaging with Graphene

“…It is also important that the SPs excited on graphene can be simply manipulated by external parameters [ 75 , 76 , 77 ]. The abovementioned advantages of graphene plasmons have made graphene a momentous candidate for a variety of practical applications [ 78 , 79 , 80 ], especially in the super-resolution imaging field [ 81 , 82 , 83 ]. Most recently, real-space imaging of acoustic plasmons in large-area graphene was experimentally demonstrated, enabling a new platform for strong light–matter interaction [ 84 ].…”

“…In 2016, Yang and coworkers proposed a graphene nanocavity on metasurface structure (GNMS) [ 83 ] to excite graphene surface plasmons at mid-infrared waveband and achieved super-resolution optical imaging by integrating the GNMS device with plasmonic structured illumination microscopy (PSIM). Figure 8 a shows the schematic of GNMS and one can see that two layers of graphene are involved to form a cavity filled with water.…”

“…( b ) Cross section of the GNMS. Reprinted with permission from [ 83 ]. Copyright 2016 Springer Nature.…”

“…( d ) Normalized intensity of normal epifluorescence microscopy (red) and GNMS-assisted PSIM (green). Reprinted with permission from [ 83 ]. Copyright 2016 Springer Nature.…”

Far‐Field Superresolution Imaging via Spatial Frequency Modulation

“…Most importantly, the propagation length and the effective refractive index can be dynamically tuned by adjustment of the chemical potential of graphene through applying temperature field, [273] magnetic field, [274] or electrical field. [270] Thanks to these inherent properties, researches on GPs have made remarkable progress [275,276] and found comprehensive applications in transformation optics, [277,278] nanoimaging, [105,[279][280][281] and tunable metamaterials. [273,282,283] Besides, the developments on upconversion fluorescent nanoparticles, that converse nearinfrared (NIR) light to visible wavelengths, [284,285] have made it more easier to facilitate the visible superresolution imaging using GPs in the NIR range.…”