Lasers, as well as light-emitting, ultrasound, and radio energy generating machines, produce frequency waves in a wide variety of forms and intensities that are aimed at different parts of the skin and the structures of skin. Which device is selected and what its output will be in order to treat a particular problem are determined by the physician or technician. Some wavelengths target blood and therefore reduce the appearance of surfaced veins and capillaries, while others affect melanin in order to reduce or eliminate brown skin discolorations; still others stimulate collagen production, reduce wrinkling, and improve the appearance of scars.
Just to be clear, all photorejuvenating machines hurt, some more than others, but none of them are pleasant. Ironically, the more it hurts, the better the results.
Of the many machines a doctor can use, which include intense pulsed light (IPL) or radiofrequency (Thermage), by far the most well-known are lasers. Laser is an acronym for Light Amplification by Stimulated Emission of Radiation. Lasers work by generating a concentrated and penetrating stream of pulsed bright light that can be controlled and strategically directed over the skin.
Two types of lasers are used in photorejuvenation, ablative and nonablative. An ablative laser literally vaporizes and removes deep wrinkling and scars from the surface of skin and penetrates deeper into skin tissue, reorganizing and stimulating production of collagen and elastin fibers in the process.
Ablative laser resurfacing uses extreme heat to remodel the collagen in skin and it is very effective for that purpose, offering dramatic results. However, ablative lasers absolutely do cause damage to skin, healing takes awhile, and the procedure runs a far higher risk of complications. Strangely enough, the positive impact ablative lasers have on skin is a direct result of the damage they cause. Ablative lasers include the CO2 Pulse laser, the Er:YAG laser, and the Q-Switched Ruby laser.
To address the issues associated with ablative laser resurfacing, a new generation of lasers was developed that pixilated or created fractional light output of the pulsed light, reducing the damage and risk. These machines cause severe redness, similar to a severe sunburn, and require subsequent treatments, but have fairly impressive results (Source: Lasers in Surgery and Medicine, September 2008, pages 454-460). One of these types of machines is called the Fraxel.
Nonablative laser treatments use a level of energy that does not damage skin. They pose minimal risk but also have less-impressive results and require multiple treatments and yearly maintenance. Lots of nonablative lasers are being used today, but some of the more popular ones include the N-lite laser, Nd:YAG laser, Flashlamp laser, the Pulsed-Light laser, and the CoolTouch laser.