Ultrafast FemtoFiber Lasers for Multiphoton Microscopy

Microscopy using ultrashort laser pulses

Multiphoton microscopy strikingly enhances the optical resolution due to the stimulation of non-linear absorption in the focal region consisting of highest power density only. This technique requires a pulsed light source for the two- or multi-photon excitation of the respective fluorophores or sample material.

Fiber Lasers for Multiphoton Microscopy

In the last two decades Titanium:Sapphire (Ti:Sa) lasers were frequently employed as workhorse in many multiphoton setups, since they offered wavelength tunability and high output power at femtosecond pulse durations. Meanwhile modelocked fiber lasers became highly attractive for multiphoton microscopy, since Ti:Sa oscillators suffer from high complexity and challenging alignment routines. Here Toptica’s FemtoFiber lasers offer a broad variability in terms of wavelength, pulse energy and duration while these laser intrinsically do not demand any maintenance, alignment or water cooling.

Additional benefits arecompactness, outstanding mode locking stability (SAM modelocking), ease-of-use and a competitive price. Toptica’s FemtoFiber lasers are ready to become the future workhorse for multiphoton- and other advanced microscopy techniques, like broadband Raman or other time resolved applications.

A widespread and important application ideally suited for the novel FemtoFiber dichro bioMP laser operating at 780 and 1050 nm is the 2-photon excitation is frequently used for live-cell imaging, due to a reduced photodamage compared to 1-photon excitation. Here the Erbium and Ytterbium pumped fiber laser of the FemtoFiber family offer wavelength also above 1 µm to allow for deeper penetration of the excitation beam in the investigated tissue.

FemtoFiber ultra 920 for Two-Photon Microscopy

The excellent performance of the FemtoFiber ultra 920 for two-photon microscopy is demonstrated in a proof of concept experiment by the research group of Prof. Thomas Hellerer at the University of Applied Science in Munich. Using the FemtoFiber ultra 920, high-resolution two-photon microscopy images of a human stem cell expressing GFP attached to its actin network are recorded, clearly resolving the actin network within the cell (Fig. a). In addition, the FemtoFiber ultra 920 can be used for two-photon microscopy of e.g. human stem cells with ATTO594 labeled actin and a DAPI labeled nucleus (Fig. b), S.pneumoniae bacteria labeled with ATTO425 (Fig. c), or other fluorophores suited for two-photon excitation at 920 nm.

Toptica’s third generation of FemtoFiber lasers are designed to cover the needs of scientists and professionals working with advanced multiphoton microscopy and spectroscopy instruments worldwide.