We have developed high-speed and high-resolution spectral domain optical coherence tomography at 1.3 µm using an InGaAs line-scan camera and a broadband light source with the bandwidth of 170 nm that produces a theoretical axial resolution of 4.4 µm in air. We compared axial resolutions from point spread functions (PSFs) and depth ranges while changing the full spectral bandwidth detected by the camera and describing the optimization process for the axial resolution, the depth range, and the sensitivity for SD-OCT system. We found that SD-OCT at 1.3 µm cannot satisfy the conditions both below the axial resolution of 5 µm and above the depth range of 2 mm because of the restricted pixel number of the line-scan camera. To scan a large depth range, the axial resolution has to be sacrificed. In addition, the sensitivity rolls off slowly as a function of the depth if a large depth range is scanned. On the other hand, if the axial resolution needs to be close to the theoretical one, the depth range becomes limited and the sensitivity decays quickly. Since we have to maintain a reasonable depth range of 2.0 mm, we chose the spectrum full bandwidth of 214 nm captured by the detector to balance the axial resolution of 8.2 µm. In this setting, the sensitivity of our OCT system was measured at 107.1 dB. Theoretical and experimental results are compared and presented in this paper.

中文翻译：

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1.3 $\mu$m 谱域光学相干断层扫描的轴向分辨率、深度范围和灵敏度优化


我们开发了 1.3 µm 的高速高分辨率谱域光学相干断层扫描，使用 InGaAs 线扫描相机和带宽为 170 nm 的宽带光源，在空气中产生 4.4 µm 的理论轴向分辨率。我们比较了点扩散函数 (PSF) 和深度范围的轴向分辨率，同时改变了相机检测到的全光谱带宽，并描述了 SD-OCT 系统的轴向分辨率、深度范围和灵敏度的优化过程。我们发现，由于线扫描相机的像素数有限，1.3 µm 的 SD-OCT 无法同时满足低于 5 µm 的轴向分辨率和高于 2 mm 的深度范围的条件。为了扫描大深度范围，必须牺牲轴向分辨率。此外，如果扫描较大的深度范围，则灵敏度会随着深度的变化而缓慢下降。另一方面，如果轴向分辨率需要接近理论分辨率，深度范围就会受到限制，灵敏度会迅速衰减。由于我们必须保持 2.0 mm 的合理深度范围，因此我们选择探测器捕获的 214 nm 光谱全带宽来平衡 8.2 µm 的轴向分辨率。在此设置下，我们的 OCT 系统的灵敏度测得为 107.1 dB。本文对理论结果和实验结果进行了比较和介绍。