Femtosecond lasers offer high optical peak powers over an extremely short period of time.  This makes several unique imaging and spectroscopy methodologies possible.  Femtolite F/G/H and FD lasers provide the robustness and reliability that is required for clinical and industrial applications, as well as in practical laboratory settings.

Two-photon excited fluorescence microscopy in live mouse brain shows pyramidal neurons (green) and blood vessels (red).

In a multiphoton fluorescence process, two or more photons are simultaneously absorbed by a molecule, which then emits a single photon at a different wavelength as it relaxes back to its ground state. A femtosecond laser is required because the probability of simultaneous absorption depends strongly on the intensity of the light. Sufficiently high intensity is only generated at the laser focus so that 3-dimensional mapping is possible without the use of a pin-hole or aperture, as with confocal microscopy. This leads to higher resolution and the ability to identify specific features with greater accuracy than single-photon confocal imaging. The ultrashort pulse duration means high peak power levels can be achieved at the sample while maintaining low average power. The low average power reduces cell toxicity and heat-related effects in the sample.

In second harmonic (SHG) and third harmonic generation (THG) imaging, the incident light converts into short wavelengths.  Femtolite lasers are highly suitable to study collagen structures in SHG imaging in semi-clinical setups because of its wavelengths and compact size, and its ease of integration into established systems.

Terahertz (THz) radiation lies between the microwave and infrared regions of the electromagnetic spectrum. Most dielectric materials, such as plastics, linen, and wood, are transparent to THz radiation. The valuable information inside the material can be obtained, non-destructively, through this radiation.  The material properties achievable include absorption, transmission, and reflection.

Femtolite F/G/H provide excellent stability and reliability with low noise in the kHz to MHz frequency range.  The compact size and rugged design enable these lasers to be used in even the most demanding fields and industrial environments.

Red Ca2 + fluorescent protein (R-CaMP1.07) in mouse brain neuron cell at 250 µm from the surface using the IMRA Femtolite FD, D-FD-1000S.

Using fluorescent proteins as labels, fluorescent protein imaging enables a broad range of experimental observations in cells and tissues. The emission of these proteins—GFP, BFP, YFP, RFP, and others—can help determine the location and dynamics of genes, molecules, and proteins.  The Femtolite FD laser has the ideal wavelengths for such in-depth imaging.  The laser delivers pulses minimizing photo-bleaching of the proteins and photo-damage of the tissue, leading to further development of in-vivo and long-time imaging.  The video is obtained by using the Femtolite FD laser, delivering pulses through fiber cable, easily integrated into the microscope.