| Traditional 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 about 200 nm. 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 super-resolution optical microscopic imaging method with annular aperture, which combines digital hologram, dark field illumination, and non-diffraction beam 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 from 1090 nm to 390 nm.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:The contribution of Vortex beam and circle Airy beam’s nondiffracting property and depth of self-focusing to the annular illumination in dark-field DHM imaging system is theoretically analyzed. The polystyrene spheres with sizes of 500 nm and 390 nm are utilized as objects in our experiment. By comparing the results of reconstructed images among vortex airy beam, airy beam, vortex beam and Gaussian beam illumination DHM, it is proved that not only the resolution of dark-field DHM with AAVB illumination is improved,but also the contrast of its reconstructed image is enhanced in the meantime. |
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