All-fiberized 1840-nm femtosecond thulium fiber laser for label-free nonlinear microscopy
Duanyang Xu, Konstantinos N. Bourdakos, Anna Crisford, Peter Johnson, Ibrahim Abughazaleh, Panuwat Srisamran, Richard O. C. Oreffo, Sumeet Mahajan, David J. Richardson, Lin Xu
Abstract
We report an all-fiberized 1840-nm thulium-fiber-laser source, comprising a dissipative-soliton mode-locked seed laser and a chirped-pulse-amplification system for label-free biological imaging through nonlinear microscopy. The mode-locked thulium fiber laser generated dissipative-soliton pulses with a pre-chirped duration of 7 ps and pulse energy of 1 nJ. A chirped-pulse fiber-amplification system employing an in-house-fabricated, short-length, single-mode, high-absorption, thulium fiber delivered pulses with energies up to 105 nJ. The pulses were capable of being compressed to 416 fs by passing through a grating pair. Imaging of mouse tissue and human bone samples was demonstrated using this source via third-harmonic generation microscopy.