History of the Laser LASER technology (Light Amplification Stimulated by the Emission of Radiation) is close to ninety years old. Albert Einstein first described and developed the laser concept in 1917. Thirty-five (35) years went by before scientists put forth more studies on laser technology. In 1954, Bell Laboratories researchers created the first MASER or "Stimulated Emissions of Microwave Radiation." Laser's real birth took place in 1960 when the first Ruby laser was created. Dr. T.H. Maiman built it at the Hughes Aircraft facilities, using a synthetic ruby rod, which generated millisecond pulses of coherent 694nm Ruby Laser light. Next came the 1060nm near-infrared laser light utilizing glass rods equipped with Neodymium (Nd: Glass Laser). In the course of that same year, Dr. Leon Goldman, dermatologist, began research on the interaction of laser light on biological systems. He used it for the first time on a pigmentary lesion, a melanoma. His early clinical studies on humans led the way to the Ruby Laser application for retinal surgery in the mid 1960's. In 1964, the Argon Ion Laser was developed. The continuous wave 488nm (blue-green) gas laser was much easier to control and provided even better suitability for retinal surgery. Still, in 1964, the Nd:YAG Laser (Neodymium: Yttrium Aluminum Garnett) and the CO2 Laser (carbon dioxide) made their entry on the market. It was the burn and learn period. Later in the 1980's the selective photo-thermolysis theory changed everything. Thus, this concept opened the way to pulsed lasers, and were prolific in regarding new applications; tattoo removal, benign skin lesion treatments, CO2 laser re-smoothing, Er:YAG laser for photo-depilation and photo-rejuvenation. Today, we resort to laser technology in many disciplines, such as: medicine (diagnostic, tumors eradication, therapeutic effects, ophthalmology), aesthetics (depilation, skin imperfection corrections), telecommunications, printing, holography, research and other industrial sciences. The current research is directed towards non-ablative laser, vision correction and improved photodynamic therapy for skin cancer treatment and hair removal. 1916 - Concept of Stimulated Emission - Albert Einstein 1958 - Laser Theory - Charles Townes and Arthur Shawlow 1959 - Optical Fiber - Sam DiVita 1960 - Ruby Laser - Theodore Maiman 1960 - HeNe Laser - Ali Javan 1962 - Semiconductor Laser - Robert Hall 1964 - CO2 Laser - Kumar Patel 1964 - Nd:YAG Laser - Guseic, Markos and Van Uiteit 1964 - Argon Laser - William Bridges 1965 - Dye Laser - Sorokin and Lankard THE LASER PRINCIPLE The LASER term originates from the acronym "Light Amplification Stimulated by the Emission of Radiations". The light penetrates the skin's surface and transforms into heat that radiates on a small given skin surface, with superior intensity. The light penetrates into the skin only a few millimeters in depth according to the chromophores targeted. The structure that absorbs the rays is called chromophore. Regarding LASER hair removal, the targeted chromophore is the melanin. The optimum goal chromophore. Regarding LASER hair removal, the targeted chromophore is the melanin. The optimum goal is for a laser to aim for efficiency without any surrounding tissue damage. What needs to be protected at all costs is the bulb's neighboring skin, meaning the peri-follicular's collagen. If altered, it may change the skin texture or scarring may arise. There are three major components in the laser: The active field (gas, solid-state, semi-conductor and chemical/coloured) The pumping mechanism The optical resonator SOLID-STATE LASER Glass or crystal rods create the active fields of these lasers. They supply an effective power capacity and operate, in a general manner, on the pulse mode. The main reason for pulse mode is to preserve the small glass rods. The active field or rods may be damaged when heat is arising. Therefore, the pulse mode slows down the deterioration process. Solid-state lasers cover a wide electromagnetic spectrum range, going from infrared to ultraviolet. A large selection of solid-state laser equipment comes with cooling systems in order to cool down the skin layers before every light pulse. This option is certainly useful in preventing skin damage. The most recent models come with the Q-switched option, used primarily to remove tattoos. Variables in Consumers That Affect Results Lasers can be useful for surface dermatological procedures like removing some kinds of tattoos and birthmarks like port wine stains. That's because the target is superficial and often in depth and colour compared to hairs. Hairs in any given treatment area can be widely variable in diameter, colour, and depth. This poorly delineated target makes laser effectiveness hard to predict. The same amount of laser energy will have different effects on hairs with different widths. Some hairs are as deep as 7 millimeters. It's hard for a laser to be effective at those depths without overheating the upper skin. Obviously, if a laser targets melanin, the less melanin you have in your hair means the less effective a laser will be. That's why someone with gray, red, or blonde hair is not as good a candidate for laser hair removal. In addition, the more melanin in your skin, the darker it looks. Whites typically don't have much skin melanin, while Blacks have more. The laser doesn't distinguish between melanin in hair and melanin in skin. That means the more melanin in a skin, the more the laser is going to be absorbed by the skin. That's why someone with darker skin is not as good a candidate for laser hair removal, however with an experienced laser operator and laser that can treat darker skin types, these individuals can still have good results. Light skin and dark hair are the best combination for laser hair removal. The more closely your skin tone matches your hair colour, the less likely you are to benefit from laser hair removal.