Repetition-Controllable Gain-Managed Nonlinear Fiber Amplifier for Biological Imaging

Nonlinear microscopy imaging of biological samples requires high peak power ultrashort pulses for enhanced signals [1]. At equal pulse energies, there exists a tradeoff: low repetition rates minimize thermal damage, while high rates maximize fluorescent photon generation [2]. Fiber lasers offer advantages over solid-state lasers in compactness and reliability for biomedical applications. While gain-managed nonlinear amplification (GMNA) [3] enables shorter pulses through controlled nonlinearity and dispersion, current mode-locked fiber lasers are constrained by fixed repetition rates (10–100 MHz), limiting optimization for different biological imaging applications.