Cr: forsterite laser at 1230?? nm. By acquiring the whole nonlinear spectrum in the visible
and near-NIR region, this novel technique allows a combination of different imaging
modalities, including second-harmonic generation, third-harmonic generation, and multiple-
photon fluorescence. Combined with the selected excitation wavelength, which is located in
the IR transparency window, this microscopic technique can provide high penetration depth …