Have you wondered what the most suitable wavelength is for the treatments you want to do?

The wavelength is often taken out of context in marketing material when you look at equipment. The most important function of the wavelength is that it determines the target (or you can also say that the target determines the wavelength). This means that the wavelength determines the types of treatment(s) that can be performed with a specific machine.

For this reason you never get a machine that can do everything.

The depth of the target molecule will determine the penetration depth for the laser energy. If your target is water, the energy will not penetrate the skin at all, because the epidermis already contains a lot of water.

However, this is not that simple. The penetration depth is influenced by various parameters.

Before you choose a machine or wavelength, you need to know which molecule(s) you should aim for to achieve an optimal result. At the same time you must know how to deal with unwanted absorption. A well-known example of this is the protection of the epidermis during laser hair removal. The target, melanin, is present in the epidermis and in the hair itself. For safe and effective results you need to heat the melanin in the hair, but at the same time you have to ensure that the melanin in the epidermis remains at a low temperature.

Wavelengths for hair removal.

Effective absorption of melanin – the main hair chromophore – occurs within the range between 600-1100 nm. Wavelengths below 600 nm are strongly absorbed by micro-blood vessels and therefore cannot be used for hair removal; Wavelengths above 1400 nm are strongly absorbed by water in the tissue.

Wavelengths for ablative lasers.

Ablative lasers such as CO₂ and Er:YAG focus on water as the primary target molecule and are therefore in a wavelength range above 2000 nm.

Wavelengths for tattoo removal.

When you are dealing with tattoo removal, you will also have to look at different wavelengths to achieve good results on different colours.

Modern tattoo removal use Q-switched and picosecond lasers. The three most common wavelengths are: Nd:YAG; Ruby and Alexandrite.

Nd:YAG (532nm)	Ruby (694nm)	Alexandrite (755nm)	Nd:YAG (1064nm)
Red ink Orange ink Purple ink Tan ink	Blue ink Sky blue ink Black ink Green ink Violet ink	Black ink Blue ink	Black ink Dark blue ink Brown ink

Do NOT attempt tattoo removal with an IPL or long pulse laser, as this can lead to severe skin damage.