Thanks to confocal Raman spectroscopy we have been able to investigate in vivo the epidermis chemical composition in its thickness. In depth measurements allowed us to observe modifications of the relative concentration of some components (water, proteins) depending on the depth in the skin and on its state of hydration.

The use of larger numerical aperture objectives would be helpful to emphasize the in-depth variations because of the possible gain in axial resolution and therefore in-depth discrimination. Indeed, the operator could then probe in depth with a smaller step size.

As a possible gain on the above measurements, the use of more powerful commercially available NIR diode lasers would yield up to ten times more laser power at the sample (60-80 mW) and would result in a tremendous improvement in terms of signal collection and integration time.