Denis Tikhoruk, General Director of Medicalaser

Natalya Dobryanskaya , dermatovenereologist of category I, practicing cosmetologist since 2005, specialist in laser and injection technologies, methodologist at Medicalaser

Laser radiation is light, but special. He is strengthened, his energy is high. Lasers are used in various fields of human activity. In this article, we will look at the applications of neodymium lasers in the beauty industry and their use in tattoo removal and permanent makeup procedures.

Laser radiation is obtained using special devices - lasers (laser emitters). If you do not go into technical details and put it simply, then a laser device is able to generate energy in the form of powerful light, amplify this light and make it uniform in wavelength. Due to this, an exceptionally high radiation density is created when focusing on a small area of \u200b\u200bthe object that the laser beam hits, for example, on human skin.

The laser has many useful properties, but for a story about the use of lasers in cosmetology, we are most interested in such properties as:

• monochromaticity (strict homogeneity of the wavelengths of the emitted light), due to which laser radiation can be absorbed and affect some substances, for example, pigments, but not absorbed and does not affect other substances that may be in the affected area - the skin ;
• narrow focus (the ability to make the laser beam very thin), due to which the laser beam can act selectively on small objects without affecting nearby ones - for example, destroying the pigment in the skin, while minimally affecting the surrounding tissues.

A bit of history

In 1960, Theodor Maiman created the first working laser, in which the radiation was generated by a ruby crystal. It was the ruby laser that was later used for the first time to remove tattoos, but had a drawback - a low frequency of flashes of laser radiation and a long flash duration, measured in milliseconds, which was too long for cosmetology purposes.

Then came the alexandrite laser, in which the radiation was generated by a crystal of the mineral alexandrite. Further development of laser technologies has led to the emergence of a neodymium laser, which is firmly entrenched in cosmetology due to the fact that it has significant advantages over ruby and alexandrite lasers.

Nd:YAG is a neodymium laser that emits infrared light of a wavelength that is very well absorbed by tattoo pigments, permanent makeup, chromoproteins (melanin of the skin, hair, hemoglobin and others), as well as various impregnations in the skin, any chromophore, even white, including aniline dyes and carbon (carbon). The emitter in a neodymium laser is a crystal (crystal rod) of yttrium aluminum garnet (YAG), which is doped with neodymium (Nd) ions during the crystal growth process. It is the addition of neodymium to a garnet crystal that gives it the necessary properties to generate radiation, which is very useful for cosmetic procedures.

The first models of neodymium lasers had disadvantages: for example, the pulse length was long - from 3 to 300 ms, and such a long-pulse laser could only be used for procedures on the first skin phototype, since burns occurred when used on the 2nd–5th phototype. The development of neodymium lasers has led to short-pulse lasers that are safe, accurate, predictable, controllable, and highly efficient. It is on their basis that laser systems for tattoo removal and permanent makeup have been created, which have firmly occupied their niche in the modern beauty industry, in cosmetology.

Let's consider modern solid-state neodymium lasers using the Nano-Light and Pico-Light laser devices as an example.

Principles of operation of modern lasers

Nano-Light and Pico-Light laser devices generate ultrashort radiation pulses with a duration in the range of nano- and picoseconds based on Q-switch technology. Such a very short duration was not available in the ruby and alexandrite lasers previously used in cosmetology.

The system for generating and controlling laser radiation in devices using neodymium emitters makes it possible to obtain a pulse with a wavelength of 1064 nm. This wavelength can be changed up to 755, 532, 355, 266, 213 nm using special additional converter tips. The possibility of obtaining such a large number of wavelengths at the output of one laser device makes it possible to carry out a large number of cosmetic procedures.

The principle of operation of laser radiation of short-pulse Nano-Light and Pico-Light devices on the pigment consists in the action of an ultrashort laser pulse, in which energy is selectively transferred only to pigment particles (which actively absorb energy of a certain wavelength), but without heating the surrounding tissues. Namely, the absence of tissue heating reduces the risk of tissue damage and subsequent scarring. The pigment particles are very quickly and strongly heated, due to which they are destroyed, crushed into smaller parts, which are then quite simply removed from the human body by the lymphatic system.

Rice. 1. Laser exposure to pigment particles

Nano- and picosecond neodymium lasers universally affect pigment accumulations of all colors and at any depth in the skin, which is another huge plus for their use in cosmetic tattoo removal and permanent makeup procedures. The depth of the pigment in the skin most often corresponds to the thickness of the epidermis, but sometimes it penetrates into the upper layers of the dermis. The thickness of the skin of an adult in different parts of the body varies from 0.5 mm on the eyelids and lips to 5 mm on the trunk. The beam of a neodymium short-pulse laser reaches the target in any case, even if the pigment is very deep, as it penetrates up to 6–8 mm.

Rice. 2. Penetration depth of pigments during procedures

Procedures performed on neodymium lasers with Q-switch technology:

• removal of tattoos and permanent makeup of various colors;
• laser carbon peeling - "Hollywood cleaning";
• fractional rejuvenation;
• treatment of hyperpigmentation (only with a picosecond laser);
• treatment of onychomycosis;
• treatment of acne, demodicosis and other dermatological diseases.

The material was first published in Permanent No. 3(11)/2018