Pulsed lasers for wavelength versatile microscopy

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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.