58 research outputs found

    Imaging in scattering media via the second-order correlation of light field

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    Imaging with the second-order correlation of two light fields is a method to image an object by two-photon interference involving a joint detection of two photons at distant space-time points. We demonstrate for the first time that an image with high quality can still be obtained in the scattering media by applying the second-order correlation of illuminating light field. The scattering effect on the visibility of images is analyzed both theoretically and experimentally. Potential applications and the methods to further improve the visibility of the images in scattering media are also discussed.Comment: 4 pages, 3 figure

    Diplexers and multiplexers design by using coupling matrix optimisation

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    Microwave filters and multiplexers are used in many application areas and have been studied for decades. However, with increasing demands on communications and radar systems more complex filters are required which not only have superior performance but also are required to be small and lightweight. This thesis looks at new techniques in microwave filter design to achieve these aims. Coupled resonator circuits are of importance for design of RF/microwave narrow-band filters with any type of resonator regardless its physical structure. The coupling matrix is used to represent the coupled resonator circuit. Each matrix entry value refers to a physical dimension of the circuit. The response of the circuit can also be calculated by using the coupling matrix. Different methods are developed to generate the coupling matrix. This thesis presents designs of the coupled resonator based diplexers and multiplexers by using the coupling matrix local optimisation technique. The design procedures and measurement performance of 3 X-band (8.2-12.4 GHz) rectangular waveguide circuits, including a 10th order diplexer, a 4th order diplexer with cross-couplings and a 4-channel multiplexer, are presented. A novel computer-aided physical structure tuning technique, called Step Tune method, is also presented in this thesis

    Ghost imaging without beam splitter

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    Many significant results have been achieved in the fields of ghost imaging, in which the beam splitter is an indispensable optical component. This paper introduces a method to realize ghost imaging without beam splitter. And we study this method experimentally and theoretically. Finally, we suggest that our device can be applied to implement the ghost imaging when we use the Sun light as the light source

    All-resonator-based waveguide diplexer with cross-couplings

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