Wavelength Separation Tunable 2-Color Soliton Generation and Its Application to 2-Color Fluorescence Multiphoton Microscopy

Optical solitons generated through soliton self-frequency shift in optical waveguides, has found the widespread applications in multiphoton microscopy (MPM). The multicolor fluorescence MPM, involving the simultaneous imaging of multiple structures labeled by different fluorophores, typically necessitates multiple-color pulses whose wavelengths match the peak excitation wavelengths of the fluorophores. Here we demonstrate experimentally an efficient method of generating wavelength separation tunable 2-color solitons, based on our recently proposed theoretical scheme of prechirping to manipulate the soliton order of the excitation pulse. Using this method, we reach a maximum soliton separation tuning range of 190 nm, with 1550-nm excitation. As an experimental demonstration of the applicability of this technique, we further show the MPM results using this 2-color soliton source for 2-color, 3-photon fluorescence imaging of fluorescent beads.