Xu Jingjiang, Wei Xiaoming, Yu Luoqin, Zhang Chi, Xu Jianbing, Wong K K Y, Tsia Kevin K
Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam Road, Hong Kong, China.
Biomed Opt Express. 2015 Mar 18;6(4):1340-50. doi: 10.1364/BOE.6.001340. eCollection 2015 Apr 1.
As the key prerequisite of high-speed volumetric structural and functional tissue imaging in real-time, scaling the A-scan rate beyond MHz has been one of the major pursuits in the development of optical coherence tomography (OCT). Along with a handful of techniques enabling multi-MHz, amplified optical time-stretch OCT (AOT-OCT) has recently been demonstrated as a viable alternative for ultrafast swept-source OCT well above MHz without the need for the mechanical wavelength-tuning mechanism. In this paper, we report a new generation of AOT-OCT demonstrating superior performance to its older generation and all other time-stretch-based OCT modalities in terms of shot-to-shot stability, sensitivity (~90dB), roll-off performance (>4 mm/dB) and A-scan rate (11.5 MHz). Such performance is mainly attributed to the combined contribution from the stable operation of the broadband and compact mode-locked fiber laser as well as the optical amplification in-line with the time-stretch process. The system allows us, for the first time, to deliver volumetric time-stretch-based OCT of biological tissues with the single-shot A-scan rate beyond 10 MHz. Comparing with the existing high-speed OCT systems, the inertia-free AOT-OCT shows promises to realize high-performance 3D OCT imaging at video rate.
作为实时高速体结构和功能组织成像的关键前提，将A扫描速率扩展至兆赫兹以上一直是光学相干断层扫描（OCT）发展的主要追求之一。除了少数能够实现兆赫兹以上的技术外，放大光学时间拉伸OCT（AOT-OCT）最近已被证明是一种可行的替代方案，可用于远超兆赫兹的超快扫频源OCT，且无需机械波长调谐机制。在本文中，我们报告了新一代AOT-OCT，在逐次稳定性、灵敏度（约90dB）、滚降性能（>4mm/dB）和A扫描速率（11.5MHz）方面，其性能优于旧一代以及所有其他基于时间拉伸的OCT模式。这种性能主要归因于宽带紧凑锁模光纤激光器的稳定运行以及与时间拉伸过程在线的光放大的综合贡献。该系统首次使我们能够以超过10MHz的单次A扫描速率提供基于时间拉伸的生物组织体OCT。与现有的高速OCT系统相比，无惯性的AOT-OCT有望实现视频速率的高性能3D OCT成像。
