A better question and the one you might have wanted to ask is what is the difference between non ablative and ablative Laser Resurfacing for the skin. Nonablative is usually done through radiofrequency, or other wavelengths that go deeper in the skin to stimulate the deeper tissues to tighten up the skin. Wavelengths from 1300-1600 achieve this non ablative skin tightening. Radiofrequency is another way of doing this via thermage, etc. These devices although not removing the layers of the skin, can cause significant swelling and redness and this can lasts a couple of days to more time. The ablative lasers such as co2 (Active fx, etc), and erbium yag lasers remove the top layers of the skin (ablate) and allow stem skin cells from within the hair follicles to resurface the treated areas to rejuvenate skin by decreasing wrinkles, tightening skin, decreasing pore size, removing unwanted pigmentation and removing precancerous skin cells. The strength of ablative or non ablative lasers really depend on what energy use and can be set by your doctor.
Here is a live demonstration of my use of a co2 laser and laser resurfacing.
Dr Young is located in Bellevue near Seattle, Washington