How to choose a diode laser for hair removal

The popularity of laser diode hair removal is gaining rapid momentum. This is due to many factors:

1. Lower cost of laser diode devices in comparison with solid state ones.
2. Quite effective contact cooling, which is implemented using Peltier elements.
3. No costs for supplies.
4. The most actively developing area of ​​laser devices in connection with the active development of semiconductors and diode technologies.

All these advantages give the idea that a diode laser has obvious advantages compared to other laser devices, but is it all so obvious in order to choose a diode laser for hair removal? Let’s try to objectively and technically evaluate all the advantages and disadvantages of the diode device.

The price of a diode laser for hair removal

The cost of a diode device for hair removal, as a rule, takes an intermediate value between the price of photoepilators and, for example, the price of alexandrite laser devices. The low price of the photoepilation machine is understandable – there are no optical elements besides the flash lamp, so the design of such a product is quite elementary. The other side of the low-cost IPL epilator is the extremely low resource of flash lamps, the lifetime of which barely reaches 100 thousand flashes, and, accordingly, with the active work of a beauty salon or clinic, these lamps need to be changed every week. Alexandrite laser, on the contrary, has a large number of complex optical elements and assemblies, which leads to its high price. On the other hand, the design of an alexandrite solid-state laser allows it to generate radiation with very high characteristics, which allows the most efficient laser hair removal procedure.

The difference between the characteristics of a diode laser from an alexandrite solid-state laser

Currently, laser diodes are capable of generating virtually any laser radiation, although the most popular in the market of aesthetic laser medicine are wavelengths of 755, 808 and 1064 nm. Alexandrite laser also generates radiation at a wavelength of 755nm, so what is the difference? The fact is that when choosing a diode laser for hair removal, one should not forget about other characteristics and parameters of laser emitters:

1. A very important parameter is the width of the spectral line of radiation. If alexandrite generates strictly at a wavelength of 755nm, then a diode laser at the same wavelength does not generate strictly at that wavelength, but in a very blurry wide range, which violates the principle of photo selectivity and accuracy of action on a particular chromophore. During a responsible medical procedure, no doctor would ever think of using, for example, an ax with a wide blade instead of a sharp scalpel?
2. Also a very important factor is the peak power in combination with the pulse duration. Everyone knows the concept of VTR (thermal relaxation time) of a target and the importance of this factor for effective and safe action on chromophores. The advantage of a solid-state alexandrite laser is the ability to achieve large peak powers, and, accordingly, to vary the duration of the radiation pulse in a wide range, adjusting to the desired chromophore. Diode lasers do not fundamentally have a large peak power, therefore they are able to generate high energy for hair removal only at very long pulse durations, which leads to overheating of the skin due to heat transfer from the hair follicles to the dermis and, accordingly, to painful sensations and the likelihood of burns. That is why diode lasers are not purely technical lasers, but occupy an intermediate position between solid-state lasers and IPL photoepilators.

Contact cooling during diode hair removal

During some laser procedures, active skin cooling is required to minimize the risks of overheating of the skin. This is especially true for diode hair removal for the reasons described above. Because Due to its weaker characteristics, the diode beam diverges much more strongly than the beam of a neodymium or alexandrite laser, it is important that the emitting head is located close to the skin (for a solid-state laser, the distance does not matter because of the quality of the beam). Therefore, only contact cooling is always used for a diode laser nozzle. This type of cooling has its pros and cons, the advantages include:

1. Ease of use.
2. Lack of additional consumables (for example, constant freon filling for some laser systems).
3. The ability to control the temperature of the cooling plate and, accordingly, the sensitivity and safety of the patient.

The main disadvantages of contact cooling of a diode laser are:

1. The lack of visual contact with the treated area immediately at the time of the shot, i.e. the doctor is partially blind.
2. The products of the combustion of hair and microparticles of the skin move together with the cooling plate and can cause side effects or inflammation if they get into the skin’s microranes.
3. The need for careful maintenance and periodic replacement of the cooling plate.

Diode laser consumables and lifetime

The big plus of the diode laser compared to solid-state modules is the almost no consumables and the long life of the diode array. Unfortunately, here, too, is not so obvious. In standard solid state devices (alexandrite laser, neodymium, erbium, etc.), the only consumable is a pump lamp, the resource of which is several million pulses (depends on the size of the spot the doctor works with, the temperature of the coolant, etc.). This is many times longer than the life of the lamps in photoepilators, but in diode lasers, the service life sometimes reaches 100 million. outbreaks! The catch lies in the fact that the cost of replacing the lamp in solid-state lasers is in the range of 500-1000 euros, and only the pump lamp changes. In the diode laser apparatus, the entire module changes, and the cost of replacing the diode module will reach 15-20 thousand. Euro, which can completely level out such an important, at first glance, advantage.

Prospects for the development of laser handpieces and modules

The diode field of laser technology, along with solid-state lasers, is currently actively and dynamically developing. Each year, new models appear on the market with more powerful features or a wider range of applications. In this situation, diode and solid-state medical lasers have significant advantages over gas (CO2) or liquid lasers, both in terms of the appearance of new, more promising models, and the upgrade of previously acquired models.