Because it avoids the in-focus photodamage and phototoxicity problem of two-photon-fluorescence excitation, multiharmonic-generation biopsy based on a 1200-1300-nm light source could provide a truly noninvasive and highly penetrative optical sectioning of skin. We study multiharmonic-generation biopsy of fixed mouse skin. Our preliminary study suggests that this technique could provide submicrometer-resolution deep-tissue noninvasive biopsy images in skin without the use of fluorescence and exogenous markers. (C) 2003 Optical Society of America.

The orientation and different levels of crystallization in biological nanostructures are revealed by polarization dependent studies under SHG and THG microscopies.