Laser diode (LD), also known as injection laser diode (ILD), is the most common laser type found on the market today. Used in fiber optic communications, barcode readers, laser pointers, CD/DVD/Blu-ray Disc reading/recording, laser printing, and laser scanning – among other things – laser diode systems are essentially small semiconductor devices that emit coherent radiation in the infrared or visible spectrum when current passes through them. First demonstrated in 1962 at both General Electric and IBM labs (General Electric submitted results first and is seen as the original tester), diode laser technology today is widely used in aesthetic medical equipment. This is due to a few factors, but the most stand out reasons include the enhanced conversion, efficiency, temperature sensitivity, and cost savings. For example, the power needed to operate a laser diode is far less than its counterparts and all components of the device, including the cooling system, can therefore be far smaller.
The US Food and Drug Administration (FDA) first approved professional use of a high-powered diode laser in 1997 for hair removal. Since that time, laser diode technology has come to be seen as the most suitable technology for hair removal across the board given its safety and effectiveness for all skin and hair types. The laser diode targets specific chromophores in the skin then damages them by providing heat in those areas while avoiding all surrounding tissue. This effectively damages the hair follicle, disrupting natural hair growth and ensuring lasting results. Due to the success that has been seen with high-powered diode lasers in the professional market and the overall advances in laser diode technology, in 2006 the FDA even approved the first in-home use of an over-the-counter laser diode product – again for hair removal – further ensuring high-powered laser diode technology’s place in the aesthetic device market.
Since aesthetic laser diode wavelengths can vary greatly (from 375 to 1,800nm), the aesthetic market has also found a thriving business with low-powered diode lasers. Used primarily for soft tissue treatment, low-power diode lasers tend to be smaller, less expensive, and more easily used with cooling or other pain reducing methods. In fact, the market growth of low-power diode lasers led to the 2010 FDA-approval of a semiconductor laser-based over-the-counter device for wrinkle removal.
When discussing diode laser technology, it is impossible to not mention LightSheer – the gold standard of diode lasers in both safety and effectiveness. Using high-powered diode technology, LightSheer by Lumenis delivers high fluence and user-controlled pulse duration alongside effective contact cooling and high-performance yielding compression. Offering a 22 > 35mm spot size, LightSheer also provides greater depth of penetration and a significantly faster treatment. Already a leader in the aesthetic device market, Lumenis is similarly a leader in diode laser technology. Other diode laser equipment for hair removal are made by Palomar and Syneron.
Examples of common aesthetic treatment applications with corresponding diode laser wavelengths can be found in the table below:
| Aesthetic Treatment | Wavelength (nm) |
| Acne Treatment | 450, 1470 |
| Hair & Wrinkle Remover | 766, 810, 915, 1064 |
| Laser Skin Resurfacing | 810, 915 |
| Lipolysis | 1210 |
| Pigmented Lesions | 810, 940, 980 |
| Varicose Vein Removal | 940 |
| Tooth Whitening | 810, 980 |