摘要:
Femtosecond laser pulses are used to iteratively cut and image fixed as well as exsanguinated fresh tissue. Such images help to automate three-dimensional histological analysis of biological tissue. Cuts are accomplished with approximately 0.3 to 100 microJoule pulses to ablate tissue with one-micrometer precision. Permeability, immunoreactivity, and optical clarity of the remaining tissue is retained after pulsed laser cutting. Samples from transgenic mice that express fluorescent proteins retained their fluorescence to within micrometers of the cut surface.
摘要:
Temporal focusing of spatially chirped femtosecond laser pulses overcomes previous limitations for ablating high aspect ratio features with low numerical aperture (NA) beams. Simultaneous spatial and temporal focusing reduces nonlinear interactions, such as self-focusing, prior to the focal plane so that deep (˜1 mm) features with parallel sidewalls are ablated at high material removal rates.
摘要:
Temporal focusing of spatially chirped femtosecond laser pulses overcomes previous limitations for ablating high aspect ratio features with low numerical aperture (NA) beams. Simultaneous spatial and temporal focusing reduces nonlinear interactions, such as self-focusing, prior to the focal plane so that deep (˜1 mm) features with parallel sidewalls are ablated at high material removal rates.
摘要:
A system for producing ultra-high peak power pulses employs a plurality of solid state amplifying materials, such as Nd:glass, alexandrite, and Ti:sapphire, to achieve stretching of a pulse prior to amplification by a factor of approximately between 100 and 10,000. The time-stretched pulse is amplified by many orders of magnitude, illustratively 10.sup.9. After time-stretching and amplification, the pulse is then recompressed to its original duration. Pumping of the multiple solid-state elements is performed simultaneously using an alexandrite laser which is tunable between approximately 700 and 800 nm. The pumping energy has a pulse duration which is less than the fluorescence lifetime of the excited solid-state media.