Laser hair removal is the practice of penetrating the skin with (you guessed it) a laser for purposes of permanent hair removal.
During a typical laser session, the laser operator moves a laser gun to and fro on the removal site, spraying short bursts of cryogen onto the area about to be blasted by the laser. Each burst is followed one second later by a laser blast, which enters the hair follicle and, after vaporising the hair it finds, disables the follicle. This is repeated, as needed over the course of about a year, until the removal site stops growing hair completely.
The laser gun itself looks somewhat like the ultraviolet gun your dentist uses to harden acrylic fillings. Its blast radius is 18mm, thus making quick work of most removal sites.
Having a laser penetrate your skin feels kind of like being snapped by a particularly thick rubber band, or like receiving a full-on slap in the face when you have a sunburn. It is not a particularly pleasant experience, although it's absolutely cake when compared to electrolysis, and it's also about 300% faster than electrolysis. However, unlike electrolysis, it's not regulated, which means that anyone who can afford a laser gun and its charging unit can become a practitioner of laser hair removal, so use care when selecting your practitioner. Most plastic surgery places seem to know what they're doing.
Following laser treatment, the recipient remains slightly sore and the removal site appears to be sunburned, though this goes away after a couple of hours. The treatments are generally spread four to five weeks apart, depending on the removal site. Treatments done closer than four to five weeks apart often cause problems with the skin's natural pigment, sometimes producing freckles and/or permanent lightening or darkening of the site's skin.
In general, laser actually costs more than most electrologists charge; however, laser is much quicker than electrolysis and requires far fewer treatments.
The most odd thing about it is that you are forced to wear UV-protectant goggles, as the laser used to remove hair can cause blindness if it comes in contact with an unprotected eye.