Pre-chirp managed self-phase modulation for efficient generation of wavelength-tunable energetic femtosecond pulses

Self-phase-modulation-enabled spectral selection (SESS) allows generation of widely tunable femtosecond pulses. We propose pre-chirp managed SESS, in which the excitation pulse is properly pre-chirped to control the fiberoptic nonlinear spectral broadening and hence generate separated spectral lobes-a feature demanded by SESS. Besides offering improved efficiency compared with conventional energy-tuned SESS, this new method is able to reshape an input pulse of unwanted shape into a bell-shaped pulse that is desired for implementing SESS. The excellent energy scalability of pre-chirp managed SESS can produce megawatt-level femtosecond pulses widely tunable in the wavelength range of 0.86-1.3 mu m. Such a powerful source is well suited to drive multiphoton microscopy to achieve deep-tissue imaging. (C) 2020 Optical Society of America