Fig. 1. (a) Principle diagram of near-field diffraction enhanced structure illumination microscopy; (b) structure of metal grating; (c) changes of wave vector and polarization after a light beam pass through the objective

Fig. 2. (a) Spatial intensity distribution of illumination stripe excited by metallic grating under the condition of kx=kg, ky=0, and Δφ=0; (b) Fourier spatial order of illumination stripe; (c) near-field intensity distribution of metallic grating calculated by FEM

Fig. 3. Sub-wavelength imaging performance of NDESIM. (a) Point spread function (PSF) of classical wide-field imaging; (b) PSF of NDESIM; (c) normalized intensity distribution on the x axis; (d) optical transfer function (OTF) of wide-field imaging; (e) OTF of NDESIM; (f) spatial distribution of object; (g) spatial distribution of wide-field image; (h) spatial distribution of NDESIM image; (i) imaging capability of wide-field imaging and NDESIM

Fig. 4. Sub-wavelength imaging performance of NDESIM with period of metal grating of 240 nm. (a) Normalized Fourier order of illumination stripe; (b) point spread function of NDESIM; (c) optical modulation transfer function of NDESIM

Fig. 5. 2-D sub-wavelength imaging capability of NDESIM. (a) Directed solved point spread function using MAP estimation method; (b) point spread function after Lukosz filtering; (c) optical modulation transfer function; (d) normalized intensity distributions along x-axis