Quantitative Phase Measurement Techniques Based On Interferometry And Their Applications To Biomedicine

Quantitative phase measurement techniques based on interferometry have advantage of detecting phase information of object light field with high precision.Two typical examples are Phase sensitive optical coherence tomography(Phase sensitive OCT)and Digital holographic microscopy(DHM),which are widely used in the fields of biomedical sensing and imaging.The main content of this paper is studying and solving two problems with these two quantitative phase measurement techniques.One problem is how to improve the coding/decoding performance of suspension array,and the other is how to enlarge the imaging depth when tomographic imaging scattering tissues.The details are shown as follows:First,quantitative phase measurement techniques based on interferometry have been used for coding/decoding in suspension array.An optical thickness encoded suspension array has been proposed for multiplexing detection of biomolecules.Compared with existing optical decoding methods,the proposed technique has advantages of high accuracy of coding/decoding,none interference between the coding/decoding signal and the fluorescence signal,and large coding capacity.Second,the optical thickness encoded micro pieces were made,and decoded by a spectral domain OCT system.The feasibility and potential of the proposed suspension array have been demonstrated.A biomolecule binding experiment was performed by the OCT system.It was found that the dimension of optical thickness changes little in the experiment of biomolecule detection,which confirmed the reliability of using the optical thickness as the coding/decoding dimension.Third,a dual wavelength digital holographic phase and fluorescence microscope system was built as the decoding and detection platform of the proposed optical thickness encoded suspension array.The dual wavelength digital holographic phase microscopic imaging path was used for decoding micro pieces,and the fluorescence microscopic imaging path was employed for detecting quantitative information.An experiment of multiplexing detection of different kinds of biomolecules was performed to verify the ability of coding/decoding of the platform,and a concentration gradient experiment was conducted to verify the ability of quantitative detection of the platform.Fourth,optical clearing was used to improve the scattering characteristic of tissue samples,and to enlarge the effective imaging depth of a short coherence digital holographic microscope system.The experiment results demonstrated that optical clearing improves the ability of the system for inner wavefront detection and reconstruction,and decreases the cross-talk noise effectively when tomographic imaging scattering tissue samples,both of which make the imaging quality of the system for deep structures enhanced.