双球面波自全息成像

发布时间：2018-03-03 15:28

本文选题：全息成像　切入点：荧光成像　出处：《华中科技大学》2014年博士论文　论文类型：学位论文

【摘要】：对生命的探索一直是人类的研究热点。在生命科学研究中,荧光标记技术和光学成像技术的结合,使得能够观测到介观层面信息,衔接上了现有的宏观与微观信息,对生命科学研究具有重要意义。然而通用的荧光光学成像方法需要通过扫描得到三维信息,无法对三维荧光信息同时记录。全息成像技术可在非扫描条件下记录样品的三维信息,排除扫描过程对时间的消耗。其关键在于采用干涉方法记录下物光的完整信息。荧光是一种宽带光,荧光全息中如何实现荧光干涉是其中的难点；此外,荧光的信号强度较弱,全息又是一种离焦探测方式,如何充分利用荧光的信号强度是实现荧光全息成像的关键。本文以实现荧光非扫描三维成像的需求为驱动,结合荧光信号的低相干度和弱信号强度特点,系统深入地研究了宽带弱信号光的全息探测方法,以及干涉系统的光程差(Optical Path Difference, OPD)理论,基于此研究结果提出了一种适合于探测宽带弱信号光的双球面波自全息(Self-interference Holography, SH)成像方法,基于此方法建立的双球面波自全息探测系统解决了现有系统不能同时满足高信噪比和高相干度要求的难题,为实现宽带弱信号光的全息探测提供了有效途径。本文从系统成像效果,分辨率和拉格朗日不变量(Lagrange invariant)三个方面展开研究。 (1)研究了干涉系统的光程差变化,发现采用双球面波干涉时可灵活控制并减小系统的光程差,在信号强度高的小记录距离处就可实现高相干度干涉,满足了探测宽带弱信号光的高信噪比和高相干度要求。实验验证发现,采用此方法可以有效地解出波前信息,且系统的信噪比可提高3-20倍(与具体记录参数有关)。 (2)研究了自全息系统的分辨率,特别是双球面波自全息系统的分辨率变化规律和引起分辨率变化的因素,并用实验结果验证了理论分析。分析发现在球面波参考光系统中,可通过增加像方数值孔径来提高分辨率。与利用横向放大率来提高分辨率的平面波参考光系统相比,球面波参考光系统的优点是可在上述信号强度高且光程差小的近焦面提高分辨率。从而在保证系统分辨率的同时,也保证了系统的信噪比和相干度。 (3)发现当全息系统满足“空间非相干,参考光和物光都包含物体信息,用来重建像的波前是参考光与物光的共轭乘积”三个条件时,光学成像系统中的拉格朗日不变量不再成立。发现并证实了自全息成像系统的横向放大率和角放大率可以不受拉格朗日不变量限制而独立变化。
[Abstract]:In life science research, the combination of fluorescence labeling and optical imaging technology makes it possible to observe mesoscopic information, connecting the existing macro and micro information. It is important for life science research. However, the general fluorescent optical imaging method needs to obtain 3D information by scanning. 3D fluorescence information cannot be recorded at the same time. Holographic imaging technology can record 3D information of a sample under non-scanning conditions, The key is to use interference method to record the complete information of object light. Fluorescence is a kind of broadband light, in which how to realize fluorescence interference in fluorescence holography is difficult; in addition, the intensity of fluorescence signal is relatively weak. Holography is also a defocus detection method. How to make full use of fluorescence signal intensity is the key to realize fluorescence holographic imaging. In this paper, the holographic detection method of wideband weak signal is studied, which is driven by the requirement of realizing fluorescence non-scanning 3D imaging and combining with the characteristics of low coherence and weak signal intensity of fluorescence signal. Based on the theory of optical path difference Path difference (OPDs), a double spherical self-holographic (SHI) imaging method for detecting wideband weak signal light is proposed. The dual spherical surface wave autoholographic detection system based on this method solves the problem that the existing system can not meet the requirements of high signal-to-noise ratio and high coherence at the same time. It provides an effective approach for holographic detection of wideband weak signal light. This paper studies the imaging effect of the system, the resolution and Lagrange invariant of Lagrange invariant. 1) the variation of optical path difference of the interference system is studied. It is found that the optical path difference of the system can be flexibly controlled and reduced by using double spherical surface wave interference, and high coherence interference can be realized at the small recording distance with high signal intensity. It meets the requirement of high signal-to-noise ratio (SNR) and high coherence for detecting wideband weak signal light. Experimental results show that the proposed method can effectively solve the wavefront information, and the SNR of the system can be increased by 3-20 times (related to the specific recording parameters). (2) the resolution of autoholographic system, especially the resolution of double spherical surface wave autoholographic system, and the factors causing the resolution change are studied. The theoretical analysis is verified by the experimental results. It is found that in the spherical wave reference light system, The resolution can be improved by increasing the image square numerical aperture. The advantage of the spherical wave reference optical system is that it can improve the resolution in the near focal plane with high signal intensity and low optical path difference, thus ensuring the resolution of the system as well as the signal-to-noise ratio and coherence of the system. It is found that when the holographic system satisfies the three conditions of "spatial incoherence, reference light and object light containing object information, and the wavefront used for image reconstruction is the conjugate product of reference light and object light", The Lagrangian invariants in the optical imaging system are no longer valid. It is found that the lateral and angular magnification of the autoholographic imaging system can vary independently without the Lagrange invariants.
【学位授予单位】：华中科技大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：R310

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