Spectroscopic analysis of the sum-frequency response of the carbon-hydrogen stretching modes in collagen type I.

We studied the origin of the vibrational signatures in the sum-frequency generation (SFG) spectrum of fibrillar collagen type I in the carbon-hydrogen stretching regime. For this purpose, we developed an all-reflective, laser-scanning SFG microscope with minimum chromatic aberrations and excellent retention of the polarization state of the incident beams. We performed detailed SFG measurements of aligned collagen fibers obtained from rat tail tendon, enabling the characterization of the magnitude and polarization-orientation dependence of individual tensor elements Xijk2 of collagen's nonlinear susceptibility.

Multicolor light-sheet microscopy for a large field of view imaging: A comparative study between Bessel and Gaussian light-sheets configurations.

Light-sheet fluorescence microscopy (LSFM) is useful for developmental biology studies, which require a simultaneous visualization of dynamic microstructures over large fields of views (FOVs). A comparative study between multicolor Bessel and Gaussian-based LSFM systems is presented. Discussing the chromatic implications to achieve colocalized and large FOVs when both optical arrays are implemented under the same excitation objective is the purpose of this work.