Pulsed lasers for wavelength versatile microscopy

多光子显微镜使用脉冲激光在生物样品中激发荧光染料标记。激发不同的染料需要不同的波长，因此在一个样品中使用多个染料需要脉冲激光，可以同时提供许多独立的输出。在非线性晶体中，OPO将短波长的泵浦光子转换为长波长的信号和空闲的光子。通过在信号波长处构造一个谐振腔，可以实现可调谐的红外光源。单个激光泵浦两个非线性晶体将产生独立的信号波长，这是多功能非线性显微镜的理想选择。该PHD项目将开发飞秒钛宝石激光器泵浦的多晶体OPOS，该项目的实际元素将由MatLab建模来支持。非线性晶体的相位匹配特性将被定制，以提供宽带宽和宽可调谐。OPO中的参数过程将使用耦合波和全场方程来模拟。博士培训将由Heriot-Watt和SUPA的一系列模块支持，特别是B21NT1(显微镜和多光子过程组件)、B21FN2(非线性光学组件)和超快光子学(远程学习SUPA课程)。如果有相关的暑期学校，也将继续进行这些活动。

Multiphoton microscopy uses pulsed lasers to excite fluorescent dye markers in biological samples. Different wavelengths are required to excite different dyes, so using multiple dyes in a single sample requires a pulsed laser that can provide many independent outputs simultaneously. An OPO converts short wavelength pump photons into longer wavelength signal and idler photons in a nonlinear crystal. By constructing a resonant cavity at the signal wavelength, a source of tuneable infrared light can be realised. A single laser pumping two nonlinear crystals will produce independent signal wavelengths, ideal for versatile nonlinear microscopy. This PhD project will develop multi-crystal OPOs pumped by a femtosecond Ti:sapphire laser.The practical element of this project will be supported with Matlab modelling. The phase-matching properties of the nonlinear crystals will be tailored to deliver broad bandwidths and wide tuneability. The parametric processes in the OPO will be modelled using the coupled-wave and full-field equations. PhD training will be supported by a number of modules at Heriot-Watt and SUPA, specifically B21NT1 (Microscopy & multiphoton processes components), B21FN2 (Nonlinear Optics component) and Ultrafast Photonics (remote learning SUPA course). Should relevant summer schools become available, these will also be pursued.