Confocal and multi-photon imaging systems are currently miniaturized to fit them to endoscopic size requirements of
probe diameters often less than 2.8 mm. High resolution in lateral dimensions of less than 1 micron and in axial
dimensions of less than 10 microns is desired to resolve sub-cellular details of in-vivo tissue. GRIN rod lens systems
have been widely used as high numerical aperture objectives in these applications because of their small size, good
image quality and favourable geometry with plane optical surfaces, which allows easy assembly. Image generation has
been enabled by combination with coherent imaging fiber bundles, GRIN relay lenses and scanning single fibers or
photonic band gap fibers. With previous GRIN systems of maximum NA of 0.50, a resolution limit laterally of approx.
1.0 micron and axially of 5.5 to 10 microns was obtained in the case of two-photon excitation. Here, we introduce a
novel concept of a GRIN lens objective system with significantly higher NA yielding resolution improved by a factor of
two (lateral) and four (axial). The image quality of initial 1.0 mm GRIN components will be characterized by the signal
analysis of 0.2 micron fluorescent beads in the multi-photon scheme and by conventional image tests using test grids
with transmitting illumination. Potentials for further miniaturization and for changing the direction of view will be
discussed.
Sub-80nm, sub-wavelength multiphoton nanoprocessing of silicon wafers as well as 3D maskless lithography by two
two-photon polymerization in combination with five-dimensional (x,y,z, λ, τ) multiphoton analysis have been
performed with the compact near infrared MHz femtosecond laser galvoscanning microscope FemtoCut (JenLab
GmbH) as well as a modified ZEISS LSM510-NLO system. Laser excitation radiation was provided by a tuneable turnkey,
one-box Chameleon as well as a MaiTai Ti:sapphire laser oscillator. Nanostructuring of silicon wafers with oil
immersion objectives was based on NIR laser-induced periodic surface structures (LIPPS) likely due to selforganization
processes. For the first time, periodic 70nm nanogrooves have been generated in wafers which is one order
below the 800 nm laser wavelength by multiphoton phenomena at TW/cm2 transient intensities and low sub-3nJ pulse
energies. Three-dimensional two-photon polymerization in SU-8 photoresists at GW/cm2 allowed rapid prototyping
with sub-200nm precision. The same intensities have been used to image endogenous and exogenous fluorophores in a
variety of materials for target finding and the evaluation of the nanoprocessing procedures.
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