Laser surgery of skin conditions having cosmetic implications has revealed the profound psychological benefits which are unmatched by any other modality of treatment either with or without a knife. An increasingly sophisticated understanding of the biophysics of laser-tissue interactions has lead to a more efficient utilization of the present technology on the clinical side and at the same time is helping the physicists to add more and more highly selective laser systems in the armamentarium of aesthetic laser surgeons.
LASER CHARACTERISTICSLaser light is monochromatic, bright, unidirectional and coherent.
Monochromaticity:The luminous waves emitted come out with the same wavelength and energy. A single wavelength or a narrow band of wavelengths emitted allows precise targeting within tissue, while sparing adjacent structures.
The light beam emitted is extremely intense and angularly well centred. The brightness or intensity is one of the important properties and can be enhanced by techniques like pulsing and Q-switching where extremely high peak power can be delivered in nanoseconds.
Coherency:All the photons emitted vibrate in phase agreement both in space and time. Coherence is a measure of precision of the waveform. Highly coherent laser beam can be more precisely focused.
Directionality:All the photons travel in Uni direction. Directionality of the laser correlates with the emission of an extremely narrow beam of light that spreads slowly. Within the laser apparatus, efficient collimation of photons into a narrow path results in a divergence factor of approximately 1 mm for every metre travelled. Directionality allows the laser beam to be focused on a very small spot size.
