Leigh Steven Y, Chen Ye, Liu Jonathan T C
Stony Brook University (SUNY), Department of Biomedical Engineering, Stony Brook, NY 11794, USA.
Biomed Opt Express. 2014 Apr 30;5(6):1709-20. doi: 10.1364/BOE.5.001709. eCollection 2014 Jun 1.
A strategy is presented to enable optical-sectioning microscopy with improved contrast and imaging depth using low-power (0.5 - 1 mW) diode laser illumination. This technology combines the inherent strengths of focal-modulation microscopy and dual-axis confocal (DAC) microscopy for rejecting out-of-focus and multiply scattered background light in tissues. The DAC architecture is unique in that it utilizes an intersecting pair of illumination and collection beams to improve the spatial-filtering and optical-sectioning performance of confocal microscopy while focal modulation selectively 'labels' in-focus signals via amplitude modulation. Simulations indicate that modulating the spatial alignment of dual-axis beams at a frequency f generates signals from the focal volume of the microscope that are modulated at 2f with minimal modulation of background signals, thus providing nearly an order-of-magnitude improvement in optical-sectioning contrast compared to DAC microscopy alone. Experiments show that 2f lock-in detection enhances contrast and imaging depth within scattering phantoms and fresh tissues.
本文提出了一种策略，可利用低功率（0.5 - 1 mW）二极管激光照明实现具有更高对比度和成像深度的光学切片显微镜技术。该技术结合了焦点调制显微镜和双轴共聚焦（DAC）显微镜的固有优势，用于抑制组织中离焦和多次散射的背景光。DAC结构的独特之处在于，它利用一对相交的照明光束和收集光束来提高共聚焦显微镜的空间滤波和光学切片性能，而焦点调制则通过幅度调制选择性地“标记”聚焦信号。模拟表明，以频率f调制双轴光束的空间对准会在显微镜的焦体积中产生以2f调制的信号，同时背景信号的调制最小，因此与单独的DAC显微镜相比，光学切片对比度提高了近一个数量级。实验表明，2f锁相检测可增强散射体模和新鲜组织内的对比度和成像深度。
