Laser Hair Removal Technology
Hair removal using laser technology was performed experimentally for almost 20 years prior to becoming available commercially in the mid 1990s. It has now become a widely used technique in clinics in many parts of the world and its efficacy is generally accepted by dermatologists. There have been many studies concerning its safety and efficiency which have been published in the professional medical journals.
The Laser Hair Removal Process
Laser hair removal technology is based upon the technique known scientifically as selective photothermolysis (SPTL) which involves the matching of specific wavelengths and pulse durations of light to obtain an optimal effect on the region of tissue to be targeted whilst minimizing the effect on neighbouring tissue. The laser is employed in causing local damage by selectively heating dark target matter within the follicle, in this case “melanin”, that causes hair to grow.
The fundamental scientific principle involved in the process is that light is absorbed by dark objects, thus photon energy produced by the laser will be absorbed by dark material in the skin. This dark material is known as chromophore (the part of a molecule responsible for its colour) and it can be either naturally-occurring or induced by artificial means.
For all commercial hair removal lasers available at the moment, melanin is employed as the primary chromophore. Melanin is the substance within skin and hair that is responsible for its colour. It comes in two varieties:
- Eumelanin – which produces brown or black colour
- Pheomelanin – which produces blonde or red colour
Until relatively recently, because of the selective absorption of light photons, it was only possible to remove brown and black hair using laser technology, with dark hair and light skin being the ideal combination. However the latest advances in laser hair removal technology now permit the treatment of black hair in dark-skinned patients and even hair containing little or no melanin.
Laser hair removal has become increasingly popular because of its speed and efficacy, although this does dependent to an extent upon the skill and experience of the laser operator, together with the availability of different lasers to produce an optimum result.
Laser Features Affecting the Outcome of Hair Removal Treatment
Several wavelengths of photon light energy have been employed, and are today used, in hair removal treatment, ranging from visible light to infra-red radiation. The applicable lasers are characterized by the light wavelength which is emitted, and which is measured in nanometers (nm). The two most effective lasers used for permanent hair reduction are Alexandrite and Nd:YAG lasers.
- Alexandrite: 755 nm. Most effective on pale to Middle-Estern skin types.
- Nd:YAG: 1064nm. Effective on a wide range of skin types including Dark Skin
Other Laser Features
- Pulse width – The duration of the light pulse, measured in milliseconds (ms). Longer pulse widths may be safer for darker skin, whilst shorter pulse widths are more effective in disabling hair follicles.
- Repetition rate – The frequency of laser pulse emission, measured in cycles per second (Hz). This is believed to have a cumulative effect. Two or three pulses aimed at the same target with a specific delay in-between can improve the heating of an area and thus increase the hair follicle disablement rate for each treatment.
- Spot size – The width of the laser beam, measured in millimeters (mm). Theoretically, the width of the ideal beam is about four times wider than the depth of the target. Hair removal lasers have a spot size about the size of a fingertip (typically 3 to 18mm). Larger spot sizes help laser light penetrate deeper and make treatments quicker and more effective.
- Fluence – The laser light energy level, measured in joules per square centimetre (J/cm²). This is another key factor which must be at a sufficiently high level to heat the follicles enough to disable hair production.
The Quanta System Mixed Technology (MT) laser system used at the Elite Plastic & Cosmetic Surgery Group clinic permits a fine control of all variable parameters, including the ability to use Alexandrite and Nd:YAG lasers both in isolation and in combination, resulting in efficient and safe hair removal for all skin types.
For further information on Laser Hair Removal technology, the following reference article provides some interesting additional material: http://en.wikipedia.org/wiki/Laser_hair_removal