Nonlinear fibre laser sources for advanced endoscopic imaging

阻碍多光子显微镜等先进显微技术转化到临床环境中的一个关键问题是，目前对非常昂贵和复杂的超快固体激光的依赖。多光子显微镜需要近红外波长的高强度光脉冲，通过多光子吸收来激发生物分子，这到目前为止只能由钛蓝宝石激光提供。光纤激光器广泛应用于工业材料加工应用，与固态激光器相比具有许多实用优势，使其非常适合在临床环境中部署，如医院。然而，光纤激光器的标准发射波长不适合于对疾病诊断感兴趣的生物分子的多光子激发。在本项目中，我们专门为这一应用开发了一种新型的波长通用的超快光纤激光器，它利用光子晶体光纤(PCF)中的非线性波长转换。PCF将与内窥镜探头接口，内窥镜探头是桌面多光子显微镜的高度微型化版本，将被设计插入现有临床内窥镜的工作通道中。其目标是开发一种临床可部署的多光子内窥镜仪器，通过将超快光纤激光器与内窥镜探头无缝集成，使用PCF来修改发射波长以适应生物组织的多光子激发。

A key issue hindering the translation of advanced microscopy techniques such as multiphoton microscopy into clinical settings is the current reliance on very expensive and complex ultrafast solid-state lasers. Multiphoton microscopy requires highly intense pulses of light at wavelengths in the near-infrared to excite biological molecules via multiphoton absorption, which to date can only be provided by Ti:sapphire lasers. Fibre lasers, widely used in industrial materials processing applications, have a number of practical advantages over solid-state lasers that make them well suited to deployment in clinical environments e.g. hospitals. However, the standard emission wavelengths of fibre lasers are not suitable for multiphoton excitation of biological molecules that are of interest for disease diagnosis.In this project, a novel wavelength-versatile ultrafast fibre laser that uses nonlinear wavelength conversion in a photonic crystal fibre (PCF) we be developed specifically for this application. The PCF will be interfaced with an endoscopic probe-a highly miniaturised version of a table-top multiphoton microscope-that will be designed to be inserted into the working channel of existing clinical endoscopes. The goal is to develop a clinically deployable multiphoton endoscopic instrument by seamlessly integrating the ultrafast fibre laser with the endoscopic probe, using the PCF that modifies the emission wavelength to suit multiphoton excitation of biological tissue.