By varying wave vectors of excited waves, parts of different orientations in Fourier spectrum can then be obtained. Such excited waves help to realize super-resolution through the way that they scatter part of the evanescent fields of the target into the far field. As reported in Advanced Photonics, they propose localized evanescent-wave illuminations, which are excited at the silicon surface by four-wave mixing, a third-order nonlinear optical process. A more fundamental approach is needed - one that is free from near-field scanning and nanofabrication as well as fluorophores.Ī team of researchers from Shanghai Jiao Tong University recently developed an alternative way to break the Abbe diffraction limit and realize subwavelength imaging in an all-optical manner. On the other hand, far-field approaches, such as stimulated emission depletion microscopy (STED), stochastic optical reconstruction microscopy (STORM), and structured illumination microscopy (SIM), are based on fluorescent labeling, restricting them from broader applications - for instance, in the semiconductor industry. As a scanning approach, it provides high-fidelity images but is always time-consuming. The near-field approach utilizes a nanosized tip scanning over the sample and directly interacts with those evanescent fields. Moerner, for their contributions to the development of super-resolved fluorescence microscopy for life-sciences research.Ĭurrently, there are two main approaches to overcoming the diffraction limit in optics: near-field and far-field. In one instance, the 2014 Nobel Prize in Chemistry was awarded to Eric Betzig, Stefan W. In response to this problem, researchers have developed many ways to bypass the Abbe limit, showing success in different applications. According to the Abbe theory, subwavelength features are usually associated with evanescent waves, which decay exponentially with distance from the target. Meanwhile, physical sizes in current research and applications in biology and the semiconductor industry have scaled down to several nanometers, which is far beyond the ability of optical waves. For example, the best optical microscope only possesses resolution around 200 nm, but the physical size of the photolithography process with an excimer laser is around tens of nanometers. The diffraction limit, also known as Abbe diffraction limit in optics, poses a great challenge in many systems that involve wave dynamics, such as imaging, astronomy, and photolithography.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |