Multi-Wavelength Super-Resolution Imaging by Structured Illumination of Bloch Surface Waves

Multi-wavelength imaging ability is important for bio-imaging, to obtain multi-modal information of biological activities. We propose a multi-wavelength super-resolution imaging method, employing the Bloch surface waves (BSWs) supported by one-dimensional photonic crystal as subwavelength structured illumination fields. Here 488 nm (blue), 532 nm (green), and 632.8 nm (red) are chosen as the illumination wavelengths, and a two-dimensional equilateral triangular grating is designed to couple the incident plane waves to the BSWs in the all-dielectric photonic crystal. The triangular grating ensures a more uniform resolution improvement along with whole lateral directions and provides better imaging quality compared with lattice grating. In our demonstration, the resolution improvements are above 2.4 fold for the three wavelengths, and lateral resolutions are below 120 nm in the Rayleigh criterion. Moreover, as the illumination device is composed of a periodic planar structure, the larger field of view is achievable. The proposed method could achieve multi-wavelength wide-field super-resolution surface imaging while maintaining high speed, good imaging quality and bio-compatibility.