The FSX-3p provides reliable and robust three-photon excitation in a compact industrial-ready form-factor.

Mouse brain image courtesy of Tianyu Wang –Xu Group Cornell University

Three-photon (3P) calcium imaging in the mouse brain has increased substantially in the last three decades, mostly driven by the innovations in multiphoton microscopy. It is very important to fundamental the microscopic understanding of neuronal (subcellular) structures and functions, and translatable to humans. There are advantages of 3P, over traditional fluorescence and two-photon microscopy, in terms of both signal strength and
imaging contrast in the deep cortex and beyond (depths > 1 mm). 3P enables extraordinarily high spatial and temporal resolution in scattering brain tissue in vivo.

Longer laser wavelength, typically > 1200 nm approximately 150 mW average power, are best suited because of the background suppression by three-photon excitation (3PE) and the reduced tissue attenuation. Thus far mainly very expensive (>$350k) and complicated solid-state laser setups noncollinear optical parametric amplifier (NOPA, Spectra Physics) pumped by a regenerative amplifier (Spirit, Spectra Physics). Prospective Instruments
presents a NEW all-fiber design that can deliver the same result in a much smaller profile and economic package, see FSX – 3P 1280.

Selected publication 3P imaging (courtesy of Tianyu Wang):

• The maximum average power for 1300-nm 3P imaging, as a function of scanning fieldof-view and imaging depth: https://doi.org/10.7554/eLife.53205
• The optimal wavelength for imaging GCaMP is between 1300-1320 nm: https://doi.org/10.1364/BOE.10.003343 (open access)
• The application of 1300-nm 3PM for through-skull imaging: https://doi.org/10.1038/s41592-018-0115-y
• 1300-nm 3P imaging with 190 mW and another example of simultaneous 2P and 3P imaging: https://doi.org/10.1016/j.cell.2019.03.011
• A review last year covering all the papers above, plus other applications and possible technologies to combine with 3PM: https://doi.org/10.1364/OPTICA.395825
• This website from Allen Institute also contains a lot 3P information and citation: https://www.3photon.org

Related products:

FSX – 3P 1280
FSX-Series