Design of a k-space spectrometer for ultra-broad waveband spectral domain optical coherence tomography.
Design of a k-space spectrometer for ultra-broad waveband spectral domain optical coherence tomography.
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DOI：
10.1038/srep42353
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发表时间：
2017-03-07
影响因子：
4.6
通讯作者：
Li G
中科院分区：
文献类型：
--
作者：
Lan G;Li G
传统的谱域光学相干层析成像（SD-OCT）中，干涉图在波数（k）空间的非线性采样降低了深度依赖的信号灵敏度。在这里，我们报告的线性波数（k空间）光谱仪的超宽带（760 nm-920 nm）SD-OCT，其中的光栅和棱镜的组合作为色散组。应用定量射线跟踪来优化线性度并最小化色散波数的光程差。Zemax仿真被用来拟合点扩散函数的矩形形状的线扫描相机的像素，以提高像素采样率。搭建了一台实验SD-OCT系统，对该系统与传统的光谱仪的性能进行了测试和比较。设计结果表明，该谱仪与传统谱仪相比，可将k空间非线性误差从14.86%降低到0.47%（约30倍）。RMS直径的95%置信区间为5.48 ± 1.76 μ m-显著小于像素大小（14 μm × 28 μm）和艾里圆盘（直径为25.82 μm，在波数为7.548 μm−1时计算）。测试结果表明，在整个成像深度（2.2 mm）上，k空间光谱仪的衰减曲线（最大值为-5.20 dB）比传统光谱仪（最大值为-16.84 dB）的衰减小得多。
Nonlinear sampling of the interferograms in wavenumber (k) space degrades the depth-dependent signal sensitivity in conventional spectral domain optical coherence tomography (SD-OCT). Here we report a linear-in-wavenumber (k-space) spectrometer for an ultra-broad bandwidth (760 nm–920 nm) SD-OCT, whereby a combination of a grating and a prism serves as the dispersion group. Quantitative ray tracing is applied to optimize the linearity and minimize the optical path differences for the dispersed wavenumbers. Zemax simulation is used to fit the point spread functions to the rectangular shape of the pixels of the line-scan camera and to improve the pixel sampling rates. An experimental SD-OCT is built to test and compare the performance of the k-space spectrometer with that of a conventional one. Design results demonstrate that this k-space spectrometer can reduce the nonlinearity error in k-space from 14.86% to 0.47% (by approximately 30 times) compared to the conventional spectrometer. The 95% confidence interval for RMS diameters is 5.48 ± 1.76 μm—significantly smaller than both the pixel size (14 μm × 28 μm) and the Airy disc (25.82 μm in diameter, calculated at the wavenumber of 7.548 μm−1). Test results demonstrate that the fall-off curve from the k-space spectrometer exhibits much less decay (maximum as −5.20 dB) than the conventional spectrometer (maximum as –16.84 dB) over the whole imaging depth (2.2 mm).