The laser hair removal treatment uses the laser beams of several wavelengths. In fact, the laser energy varies in wavelength from visible light to near-infrared radiation. These lasers are defined by the lasing medium applied for creating the wavelength.
Various types of laser used for hair removal are as follows:
Alexandrite- 755 nm (Red) It is very effective on pale skin and is not safe on darker skin.
Pulsed diode array – 810 nm (Near-Infrared) It is used for pale to medium type skin.
Nd:YAG laser – 1064 nm (Near-Infrared) It is prepared for treating darker skin types and is generally effective on all skin types.
The Pulse width of the laser used for the hair removal is an important factor. The longer pulse widths are safer for darker skin, however shorter pulse widths are effective in removing the hair follicles. The repetition rate creates a cumulative effect and it is based on principle of thermal relaxation time. By shooting two or three pulses on the same target area with delay between pulses leads to improvement in the heating of area. It may also enhance the “kill rate” for each treatment.
The treatment is also affected by the width of the laser beam. The width of the ideal beam is approx four times in width as the depth of the target. The hair removal lasers possess a spot size of the size of a fingertip and the larger spot sizes assists in deeper penetrations leading to faster and effective treatment.
Fluence or energy level is also important parameter in laser hair removal treatment. It is measured in joules per square cm (J/cm²) and one should ensure to provide treatment at high enough settings for heating the follicles to render them unproductive for hair growth. Epidermal cooling is another factor that allows higher fluences and thereby reducing the pain and side effects in darker skin.