Confocal microscopy and multi-photon excitation microscopy of human skin in vivo.

This paper compares tandem scanning reflected light confocal microscopy and multi-photon excitation microscopy for the observation of human skin in vivo. Tandem scanning confocal light microscopy based on a white light source can provide video-rate image acquisition from the skin surface to the epidermal-dermal junction. Multi-photon excitation is induced by a 80 MHz pulse train of femtosecond laser pulses at 780 nm wavelength. This nonlinear microscopic technique is inherently suitable for deep tissue fluorescence imaging. The relative merits of these two techniques can be identified by comparing movies of optical sections obtained from the forearm skin of the same volunteer.