![]() 11- 20 We show that we can image 2D structures containing multiple spatial frequency components in arbitrary directions at subwavelength resolution. By integrating an improved image reconstruction algorithm into our SRC-based illumination, we demonstrate that our approach effectively eliminates the image blurring and distortion artifacts which plagued previous implementations of evanescent wave imaging. Here, we first introduce a super-resolution chip (SRC) capable of generating high wave vector components in the evanescent wave illumination to enable label-free, super-resolution imaging in a wide field microscope. The design of an integrated chip for label-free, far field, super-resolution imaging would thus present a significant advance for a broad range of applications. However, the label-free coherent imaging on chip without distortion and blurring has not so far been reported. Fluorescence based super-resolution techniques have also been used in conjunction with waveguides chips, 21- 25 demonstrating the potential of integrating photonic circuit technologies with super-resolution imaging. In addition, because of the lack of precise control on evanescence illumination direction, these techniques suffer from frequency-aliasing and it is impossible for them to recover the original sizes of the samples. However, the acquired images of the sample by these techniques are enlarged with different magnification factor depending on their real size and structures, suffering from serious distortions. The techniques mentioned have potential for integration with engineered substrates which can be used in conjunction with conventional brightfield microscopes. Examples include the hyperlens, 11- 14 microsphere contacting, 15- 17 microfiber illumination, 18 and nanowire ring illumination 19, 20 methods, all of which with capability of resolving subwavelength information. They are based on the scattering of evanescent waves by the sample and the designed imaging components to capture high spatial frequency information. To complement the various far field super-resolution imaging methods based on fluorescence, various label-free, coherent imaging techniques have been developed. This prevents their use for dynamic, label-free imaging, for example, in studies of the movement of subcellular organelles or in nonbiological applications, such as chip and materials inspection. However, these methods are incoherent imaging techniques and rely on the use of fluorescent labels. ![]() Fluorescence-based super-resolution techniques such as stimulated emission depletion (STED) microscopy, 1- 3 photoactivated localization microscopy (PALM), 4, 5 structured illumination microscopy (SIM), 6, 7 and stochastic optical reconstruction microscopy (STORM) 8- 10 have demonstrated improved spatial resolution to less than 30 nm, leading to breakthrough discoveries in the life sciences. ![]() To overcome this limit, various methods of far-field super-resolution microscopy have been reported over the past decades. ![]() However, in conventional microscopy, the attainable resolution is limited to around half the wavelength of the illumination light. Optical microscopy at high resolution plays an indispensable role in many areas of research, including biology, device fabrication, and materials research. ![]()
0 Comments
Leave a Reply. |