The nonuniform distribution of interference spectrum in wavenumber k-space is a key issue to limit the imaging quality of Fourier-domain optical coherence tomography (FD-OCT). At present, the reconstruction quality at different depths among a variety of processing methods in k-space is still uncertain. Using simulated and experimental interference spectra at different depths, the effects of common six processing methods including uniform resampling (linear interpolation (LI), cubic spline interpolation (CSI), time-domain interpolation (TDI), and K-B window convolution) and nonuniform sampling direct-reconstruction (Lomb periodogram (LP) and nonuniform discrete Fourier transform (NDFT)) on the reconstruction quality of FD-OCT were quantitatively analyzed and compared in this work. The results obtained by using simulated and experimental data were coincident. From the experimental results, the averaged peak intensity, axial resolution, and signal-to-noise ratio (SNR) of NDFT at depth from 0.5 to 3.0mm were improved by about 1.9dB, 1.4 times, and 11.8dB, respectively, compared to the averaged indices of all the uniform resampling methods at all depths. Similarly, the improvements of the above three indices of LP were 2.0dB, 1.4 times, and 11.7dB, respectively. The analysis method and the results obtained in this work are helpful to select an appropriate processing method in k-space, so as to improve the imaging quality of FD-OCT.

单晶光纤 (SCF) 是一种将体块晶体与玻璃光纤的优势相结合的新型一维化晶体材料, 其具有优异的物理化学以及热管理性能, 在激光、闪烁、传感等方面具有巨大的应用潜力。目前单晶光纤的主要生长方法有激光加热基座 (LHPG) 法和微下拉 (μ-PD) 法, 其中 LHPG 法生长过程中不需要使用坩埚, 可制备更小直径的单晶光纤,以充分发挥光纤的形态优势。研制了国内具有自主知识产 权的 LHPG 单晶光纤炉, 并生长了 Al2O3、YAG、LuAG 等单晶光纤, 其中 YAG 单晶光纤直径可达 200 μm, 长度为 710 mm, 长径比大于 3500:1。 同时对单晶光纤的直径均匀性、结晶质量等性能进行了研究, 结果表明准一维化的单晶光纤仍具有良好的物化性能。

单晶光纤 (SCF) 即具有光纤形态的单晶体, 不仅保持了单晶材料优异的理化性能, 而且具备光纤散热效率高的优势和光波导特性, 在固态激光、辐射探测、高温传感等领域具有潜在的应用前景。近年来, 研究人员在单晶光纤的晶体生长、包层制备技术、器件应用等领域开展了大量研究。本文围绕当前制备氧化物和氟化物单晶光纤广泛采用的微下拉法、激光加热基座法、导模法等晶体生长技术展开详细 讨论, 论述了上述晶体生长技术的原理和应用特点, 并介绍了国内外相关领域科研团队的研究进展。此外, 简要介绍了单晶光纤在高功率激光、中红外激光、辐射探测等领域的应用探索, 并探讨了单晶光纤的包层制备技术。

A simple method to objectively and simultaneously measure eye's longitudinal and transverse chromatic aberrations was proposed. A dual-wavelength wavefront measurement system using two Hartmann–Shack wavefront sensors was developed. The wavefronts of the red (639.1 nm) and near-infrared (786.0 nm) lights were measured simultaneously for different positions in the model eye. The chromatic wavefronts were converted into Zernike polynomials. The Zernike tilt coe±cient (first term) was used to calculate the transverse chromatic aberration along the x-direction, while the Zernike defocus coe±cient (fourth term) was used to calculate the longitudinal chromatic aberration. The measurement and simulation data were consistent.

在早期的研究中，采用出、入瞳直径相等的双通系统进行人眼像差测量时，两个通道的奇像差相互抵消，造成奇像差(如彗差)无法测量。本文建立全新的模拟眼模型进行实验，验证双通系统在波前测量时，是否存在人眼奇像差抵消的现象。采用典型双通系统——哈特曼波前探测系统进行实验，并将出瞳光阑直径固定为6 mm，改变系统入瞳光阑大小（1~8 mm）。实验结果表明，双通系统中，人眼奇像差在出、入瞳直径相等时可测，且人眼奇像差测量与出、入瞳直径差异无关，因此人眼奇像差测量在双通系统中不存在抵消的现象。

It is necessary to know the distribution of the Chinese eye's aberrations in clinical environment to guide high-resolution retinal imaging system design for large Chinese population application. We collected the monochromatic wave aberration of 332 healthy eyes and 344 diseased eyes in Chinese population across a 6.0-mm pupil. The aberration statistics of Chinese eyes including healthy eyes and diseased eyes were analyzed, and some differences of aberrations between the Chinese and European race were concluded. On this basis, the requirement for adaptive optics (AO) correction of the Chinese eye's monochromatic aberrations was analyzed. The result showed that a stroke of 20
m and ability to correct aberrations up to the 8th Zernike order were needed for reflective wavefront correctors to achieve near diffraction-limited imaging in both groups for a reference wavelength of 550 nm and a pupil diameter of 6.0 mm. To verify the analysis mentioned above, an AO flood-illumination system was established, and high-resolution retinal imaging in vivo was achieved for Chinese eye including both healthy and diseased eyes.

如何有效矫正随人群起伏很大的人眼像差, 提高人眼自适应光学系统的人群适用范围是临床应用面临的最大难题。旋转双柱面镜散光补偿技术是一种使用灵活、低成本的散光补偿方法。给出了旋转双柱面镜散光矫正的理论依据, 并搭建了基于远场光斑形态的散光自动补偿实验系统, 验证了旋转双柱面镜散光矫正理论的正确性。在此基础上, 将旋转双柱面镜与人眼自适应光学系统相结合, 利用哈特曼波前测量数据调整双柱面镜, 实现了(-4~0 Dc)散光的全自动补偿, 补偿精度优于0.1 Dc, 并验证了实际人眼散光补偿效果。该技术结合Badal调焦可以为人眼自适应光学系统的大规模人群适用提供一种经济有效的低阶像差补偿方案。