光学相干层析系统噪音分析(Ⅱ)——时域OCT和频域OCT

本文作为前文《光学相干层析系统噪音分析(I)》的后续,对时域OCT和频域OCT的噪音和灵敏度进行了详细的分析和计算,证明与时域OCT系统不同,频域OCT系统的信噪比与光源带宽和纵向扫描深度无关,频域OCT系统可以在高速率图像采集的情况下仍然保持探测系统的大动态范围.     

光学相干层析系统噪音分析(Ⅰ)——理论与计算

为了提高光学相干层析系统的性能,本文主要从理论上分析研究光学相干层析系统噪音和灵敏度的相关计算原理.比较了无杂散光的理想情况与非理想情况下,平衡探测与非平衡探测光学相干层析系统的噪音特性,并给出了相应计算公式,为设计和研制光学相干层析系统提供一个较为系统的理论分析依据.     

低相干光断层扫描系统的噪声分析与研究

低相干光断层扫描，是近十几年来发展起来集多种前沿科学和技术为一体的超高精度成像技术。介绍了该技术的理论原理及本实验室建立的基于时域线性调制和光纤迈克耳孙干涉仪的低相干光断层扫描系统并给出了初步的实验结果。重点对光源谱型和参考臂扫描速度不均匀性对系统输出信噪比的影响进行了理论模拟计算和实验研究。通过运用傅里叶频谱的分析方法，从工程设计的角度出发给出了基于实验结果的参量特性分析以及这些特性将会给实际光学相干层析系统测量结果带来的影响，从而获得了低相干光断层扫描系统改进的方法。     

Numerical simulation of a gradient-index fibre probe and its properties of light propagation

In order to verify the properties of the light propagating through a gradient-index (GRIN) fibre probe for optical coherence tomography (OCT), numerical simulation using the optical software GLAD is carried out. Firstly, the model of the GRIN fibre probe is presented, which is consisted of a single mode fibre (SMF), a no-core fibre (NCF), a GRIN fibre lens and an air path. Then, the software GLAD is adopted to numerically investigate how the lengths of the NCF and the GRIN fibre lens influence the performance of the Gaussian beam focusing through the GRIN fibre probe. The simulation results are well consistent with the experimental ones, showing that the GLAD based numerical simulation technique is an intuitive and effective tool for the verification of the properties of the light propagation. In this paper, we find that on the conditions of a constant GRIN fibre lens length of 0.1 mm and an NCF length of 0.36 mm, the working distance of the probe will be 0.75 mm and the focus spot size is 32 μm.