Multiphoton microscopy II: brighter images
with shorter excitation pulses

In previous weeks, we have shown how an NIR laser such as FYLA's SCH with a pulse duration of 15fs, offers more than 7 times the photon flux of a standard 100fs laser, for similar repetition rates and average power.
But what is the real impact on the image brightness of such a considerable improvement in the number of photons available per time and per area?
Theoretically, in two-photon microscopy, the image brightness is directly related to the excitation efficiency, which depends quadratically on the photon flux and the second-order nonlinear excitation cross section of the fluorophore (GM).