Localization-based full-field microscopy: how to attain super-resolved images.

Taehwang Son,Wonju Lee,Donghyun Kim

doi:10.1038/srep12365

Abstract

In this study, we have investigated localization-based microscopy to achieve full-field super-resolution. For localized sampling, we have considered combs consisting of unit pulses and near-fields localized by surface nanoapertures. Achievable images after reconstruction were assessed in terms of peak signal-to-noise ratio (PSNR). It was found that spatial switching of individual pulses may be needed to break the diffraction limit. Among the parameters, the resolution was largely determined by sampling period while the effect of width of a sampling pulse on PSNR was relatively limited. For the range of sampling parameters that we considered, the highest resolution achievable is estimated to be 70 nm, which can further be enhanced by optimizing the localization parameters.

Highlights

For quantitative evaluation of image reconstruction in localization based microscopy, a standard gray scale image of Lena in 512 × 5 12 pixels was used as an object, where the size of a pixel is assumed to be 5 × 5 nm[2], i.e., the test image is as large as 2.56 × 2.56 μ m2
All images under comparison are normalized in intensity to ensure that the image quality should not be affected by image brightness
TM The image reconstruction using unit pulse combs was calculated by Matlab in custom-built codes

Summary

Methods

For quantitative evaluation of image reconstruction in localization based microscopy, a standard gray scale image of Lena in 512 × 5 12 pixels was used as an object, where the size of a pixel is assumed to be 5 × 5 nm[2], i.e., the test image is as large as 2.56 × 2.56 μ m2. For image reconstruction based on surface-enhanced field localization, near-field calculation was performed in 3D by finite difference time domain method (mesh size: 5 × 5 nm2) assuming 488 nm as the excitation wavelength. The model for surface nanoapertures that are used to localize light waves consists of a gold film (thickness = 52 nm) patterned with nanohole arrays and a 2-nm thick chromium adhesion layer on a BK7 glass substrate. The electric field intensity distribution was calculated in the lateral plane at the middle of a nanohole along the depth axis

Results

Discussion

Conclusion