Super-resolution Optical Microscopic Imaging Method And System Based On Annular Aperture

Far-field optical microscope can achieve real-time and non-scan fast imaging in the natural environment, which can not be achieved by scanning electron microscopy (SEM), scanning tunneling microscopy (STM), atomic force microscopy (AFM), scanning near-field optical microscopy (SNOM), and etc. However, the highest resolution of conventional far-field optical microscope can only reach the half-wavelength of visible light, due to the limit of optical diffraction, and the value is about200nm. It’s difficult to meet microscopic imaging with deep sub-micron to nanometer scale, even molecular level. Therefore, how to improve the resolution of the far-field optical microscopy has always been an important and urgent question.On the basis of conventional transmission microscope, a new far-field super-resolution optical microscopic imaging method with annular aperture, which combines high brightness LED area source, narrow band filtering, and annular light-cone illumination with high numerical aperture together, is proposed in this paper. This physical model is established that this system can follow the traditional imaging method, which is real-time, direct and without scanning, and obtain better resolution than1OOnm.This paper studied the imaging method and system of the super-resolution optical microscopy from the theory, system design and experiment respectively. The main content is as follows:A new method of far-field super-resolution optical microscopic imaging based on annular aperture has been proposed, and its physical model is established. Using scalar diffraction theory, the formula of diffraction intensity on image plane is derived for annular light-cone illumination and imaging under different numerical apertures. The diffraction patterns are further simulated through simulation calculation, which demonstrates that such a method may significantly increase the microscopic imaging resolution.Super-resolution optical microscopic imaging system has been built. It includes high numerical aperture annular light-cone illumination and imaging module, the main body of the microscopic imaging system, microscopic monitoring and image acquisition module with CCD and computer software and hardware and so on. The corresponding microscopy image acquisition and processing software has been developed. The microscopic image with better resolution and better quality could be obtained with the software.Experiments have been carried out on a self-build microscopic system. It includes microscopic imaging experiments in bright field and dark field, super-resolution optical microscopic imaging experiment with different annular aperture transmittance levels. The experimental results are in good agreement with the theoretical predictions, thus proving the feasibility of this microscopic imaging method.