A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

비만아 부모의 돌봄 경험: q 방법론

Thank you for reading principles of optics electromagnetic theory of propagation interference and diffraction of light. As you may know, people have search hundreds times for their favorite novels like this principles of optics electromagnetic theory of propagation interference and diffraction of light, but end up in harmful downloads. Rather than enjoying a good book with a cup of coffee in the afternoon, instead they are facing with some infectious bugs inside their computer.

Principles Of Optics Electromagnetic Theory Of Propagation Interference And Diffraction Of Light

Quantitative phase imaging (QPI) has emerged as a valuable method for investigating cells and tissues. QPI operates on unlabelled specimens and, as such, is complementary to established fluorescence microscopy, exhibiting lower phototoxicity and no photobleaching. As the images represent quantitative maps of optical path length delays introduced by the specimen, QPI provides an objective measure of morphology and dynamics, free of variability due to contrast agents. Owing to the tremendous progress witnessed especially in the past 10–15 years, a number of technologies have become sufficiently reliable and translated to biomedical laboratories. Commercialization efforts are under way and, as a result, the QPI field is now transitioning from a technology-development-driven to an application-focused field. In this Review, we aim to provide a critical and objective overview of this dynamic research field by presenting the scientific context, main principles of operation and current biomedical applications. Over the past 10–15 years, quantitative phase imaging has moved from a research-driven to an application-focused field. This Review presents the main principles of operation and representative basic and clinical science applications.

Quantitative phase imaging in biomedicine

Proceedings of the National Academy of Sciences

The recently proposed fluorescence emission difference (FED) microscopy has been demonstrated to be capable of breaking the diffraction barrier, which restricts the spatial resolution of far-field fluorescence microscopy. In this paper, we report a novel high-speed FED system that can realize real-time super-resolution imaging. By replacing the conventional nanopositioning stage with a galvo mirror, the temporal resolution of FED is improved to nearly one frame per second, which is 100 times faster than that of best existing FED, while the system maintains a super-high spatial resolution of 150 nm, which is far beyond the diffraction barrier. Therefore, the high-speed FED is suitable for large-area observations while avoiding photobleaching. Detailed theoretical analysis, simulations, and experimental real-time resolution tests on 100 nm nanoparticles and biological cells are reported.

Real-time super-resolution imaging by high-speed fluorescence emission difference microscopy

We present a theoretical approach to extend depth of focus (DOF), which is based on the integrated utilization of the cylindrical polarization effect, circular symmetrical phase mask and interference effect. Simulation results show that this method can generate over 4λ and 2λ DOFs when objective lenses with NA = 0.9 and 1.4 are introduced respectively, while maintaining the horizontal size beyond the diffraction limit. The DOF is over two times that by conventional approaches under the same conditions. Such a focal spot with extended DOF, although stemming from the STED microscope concept, is applicable in nanolithography.

https://iopscience.iop.org/article/10.1088/2040-8978/14/4/045702/pdf

A method for extending depth of focus in STED nanolithography

The invention discloses a three-dimensional hollow light spot generating method and a three-dimensional hollow light spot generating device. The three-dimensional hollow light spot generating device comprises a laser, a single mode fiber, a collimating lens, a first polarizing beam splitter prism, a plurality of light turning assemblies, two phase modulators, a second polarizing beam splitter prism, a 1/4 wave plate, a microobjective, a sample surface and a medium film reflecting lens. The three-dimensional hollow light spot generating method comprises the following steps; performing different phase modulation on vertical polarized light and parallel polarized light; combining the two modulated light beams, and converting the combined light beam into two circuit polarized lights by the same 1/4 wave plate; projecting the two circuit polarized lights by the microobjective to penetrate through the sample surface, and reflecting the two circuit polarized lights by the medium film reflecting lens; interfering the reflected light irradiated to the sample surface with projecting light to form a transverse hollow light spot and an axial hollow light spot respectively; and superposing the light intensities of the two hollow light spots to form a three-dimensional hollow light spot, wherein the transverse size of the three-dimensional hollow light spot is 0.56 wavelengths and the axial size of the three-dimensional hollow light spot is 0.44 wavelengths. The three-dimensional hollow light spot generating method and the three-dimensional hollow light spot generating device can be applied to super-resolution microscopic equipment such as a stimulated emission depletion microscope and are used for realizing three-dimensional super-resolution microscopy.

Three-dimensional hollow light spot generating method and device

The invention discloses a multilayered liquid crystal display weight optimization device based on visual system characteristics. The multilayered liquid crystal display weight optimization device comprises a spatial light modulator array, a polarizing film array, backlighting equipment, and a control terminal, which are sequentially arranged in the human eye sight direction, wherein the spatial light modulator array is used for modulating transmittance of polarized light accessing the human eyes; the polarizing film array is used for modulating the bias light accessing the spatial light modulator array to be the polarized light; the backlighting equipment is used for providing backlight with uniform luminance to the spatial light modulator array; the control terminal is used for controlling the transmittance of RGB (Red, Green and Blue) channels of each pixel on the spatial light modulator array, so as to realize near-eye three-dimensional display. The invention further discloses a multilayered liquid crystal display weight optimization method based on the visual system characteristics. The method comprises the following steps: putting forward that the central area and the marginal area of a reconstructed light field possess different weight ranges, meanwhile combining with focused convergence conflict resolution conditions, computing the final weight angle, and enabling the optimization result to be closer to the truth. The multilayered liquid crystal display weight optimization device based on the visual system characteristics and the multilayered liquid crystal display weight optimization method based on the visual system characteristics disclosed by the invention obviously increase the optimization speed, and enhance the real-time performance of the optimization algorithm.

Multilayered liquid crystal display weight optimization method based on visual system characteristics and device

A novel ultra-fast micromixer of a quasi T-channel with electrically conductive sidewalls is presented here and some new phenomena in its mixing process are observed and reported. The mixing is about 102–103 times faster than that by purely molecular diffusion, and about 102 times faster than that in existing micromixers, which are based on the electrokinetic instability (EKI). Both parallel and non-parallel channel are investigated and compared by evaluating their mixing. Mixing behaviors in the microchannels are studied in terms of scalar concentration distributions. It is found that with a small angle (about 5° in this case) between the two electrodes sidewalls, mixing can be enhanced rapidly at even low AC voltage. The influence of the applied AC voltage phase shift between the two electrodes on the mixing process is also explored. The result reveals that the mixing is the strongest under a 180° signal phase shift. Fast mixing is also achieved under high AC frequency in this micromixer. Fluorescent mi...

Cuifang Kuang

Papers

Real-time super-resolution imaging by high-speed fluorescence emission difference microscopy

A method for extending depth of focus in STED nanolithography

Three-dimensional hollow light spot generating method and device

Multilayered liquid crystal display weight optimization method based on visual system characteristics and device

AC Electrokinetic Fast Mixing in Non-Parallel Microchannels