| Digital holographic microscopy(DHM)has the advantages of non-contact measurement,large field of view and good real-time performance,so it has a broad application prospect in surface morphology measurement of micro-nanostructures and biomedical engineering.With the development of micro-nano manufacturing technology and biomedical technology,the requirements of high resolution,high phase quality and high phase accuracy are put forward to DHM,which have become new challenges.This dissertation focuses on improving the phase quality of DHM,including ameliorating the phase of multi-angle illumination super-resolution DHM,improving the phase quality of samples in turbid media,and improving the phase accuracy of samples by using environmental concentration information.The multi-angle illumination super-resolution DHM system,transmittance infrared DHM system and the combination system of DHM and near-infrared spectroscopy are developed and built,which can achieve the purpose of ameliorating the phase accuracy,improving the phase signal-to-noise ratio of samples in turbid media,and improving the phase accuracy of biological samples.The main work of this dissertation includes:1.A multi-angle illumination super-resolution synthetic aperture method is proposed.A multi-angle illumination super-resolution DHM system realized by optical fiber is designed and built.The phase noise has been suppressed and the lateral resolution has been improved by the proposed method.The system can achieve 1.26 times lateral super-resolution.2.A method to measure biological samples in turbid media by infrared DHM system is proposed.The transmittance infrared DHM system is designed and built.Due to the influence of speckle noise,the phase cannot be reconstructed using visible holographic system when measuring biological samples in turbid media.A maximum thickness of 500 μm of turbid media where samples can be measured is achieved.3.In order to improve the phase accuracy of biological samples by using environmental concentration information,a measurement method combining DHM with near infrared(NIR)spectroscopy is proposed.A combined system is designed and developed.The system can simultaneously measure the thickness and NIR spectrum of onion epidermal cells in the experiment of plasmolysis,which proves the feasibility of the system. |
