A look at the difference between diode lasers and other types of laser suitable for hair removal. Followed by a guide for purchasing a diode laser.

The only difference between a diode laser and another type of laser is the fact that a diode laser uses a semiconductor to generate the light beam. This one difference has a wide range of implications.

The size – a diode laser chip can be less than 1 mm2. A comparative Alex or Nd:YAG laser may need a resonator to generate the same energy that can be the size of a standard 800 g bread.

Robust – a semi-conductor chip has no loose parts. While a resonator needs to be treated with upmost care not to go out of alignment. Gas or dye lasers can contain poisonous substances that also limits the machine in its movability.

Plug-n-play – most diode lasers for hair removal have the diodes in the hand-piece. If anything happens, it is easy to replace the hand-piece. If a machine has a resonator, you may have to take the machine apart to solve the problem.

Inexpensive to manufacture – laser diodes are manufactured in the billions and are cheap compared to other types of lasers.

Available in different wavelengths – laser diodes can be manufactured to irradiate almost any wavelength. With other types of lasers you are limited to one wavelength. And because diodes are so small you can combine different wavelengths in one hand-piece.

One drawback you have with most diode lasers is that the hand-piece is bulky and quite heavy. This is because of the diode being mounted in the hand-piece. Lasers with resonators come with the comfort of a smaller and light hand-piece.

How the results of diode lasers compare with other types of lasers.

The results are not related to the medium used to generate the light. The results are dependent on the overall performance of a machine. 80 J/cm2 on 1064 nm from a diode laser, and 80 J/cm2 on 1064 nm from a solid-state laser, will give the same results; if all the other parameters are the same.

The cost of a high-quality diode laser machine for hair removal is very similar to the cost of a high-quality solid-state laser for hair removal. Unfortunately, these are not the machines flooding the market at the moment.

The reason why you find so many low-end diode lasers and not low-end solid-state lasers is that the cost of manufacturing a low-end solid-state laser is still very high.

BIG MISPERCEPTION: A diode laser is safer because it always has a cooling tip.

The cooling tip on diode lasers are not there to protect the epidermis in the first place. The reason you get a cooling tip standard on a diode laser is because it is the most effective and cheapest way to keep the laser diodes cooled that is located in the hand-piece.

Most people who have used a low- to mid-range diode laser will tell you that the tip temperature goes up very quickly once you start working with the unit.

A diode laser is not inherently more or less safe than any other type of laser.

The difference between a single- and multi-wavelength diode laser for hair removal.

Multi-wavelength diode lasers are currently sold as the best thing since sliced bread. But, is it really?

There is currently no independent and conclusive evidence that a multi-wavelength machine will provide better results than a single-wavelength equivalent of that machine.

However, multi-wavelength hand-pieces come with a considerable technical cost to the machine and therefore for the machine owner.

To create a triple-wavelength hand-piece, the manufacture places three different sets of diodes, each radiating a single wavelength, in the hand-piece. The problem that arises here is that each set of diodes has a unique technical specification. The manufacture then creates an environment that will be as suitable as possible for all three, but not optimized for any one of the three.

This means that the lifetime of all three sets are reduced, as well as the optimal performance of the hand-piece.

If there is only one set of the same diodes in the hand-piece, single-wavelength, the manufacture can optimize the environment to get the best performance from that hand-piece.

A single-wavelength hand-piece can last 50% or longer than a multi-wavelength hand-piece. Over the lifetime of a machine this can add up to a considerable amount of money. Keep in mind that this differs from manufacture to manufacture.

The important factors when buying a diode laser for hair removal.

Is this specific machine legal in your country

Most people do not realize it, but not all machines are equal and neither are all machines legal in all countries.

Most countries regulate lasers under medical devices. This is because you only get two regulatory classes of lasers; medical or industrial. All lasers suitable for hair removal are class 4 medical lasers.

Check with your health authorities before you buy anything. All countries allow for confiscation of illegal medical devices. If your machine is confiscated, you have no recourse and will lose all the money you spent on the machine. PLUS you can be held liable for recycling cost and other legal charges.

Fluence

Fluence is that amount of energy spread over an area, J/cm2. Most entry-level manufactures try NOT to give the fluene of their machine on the marking material. Fluence is one of the biggest factors determining the price of a machine.

On a high-end machine it is common to see a fluence of over 100 J/cm2, while a maximum fluence of 35 J/cm2 is not uncommon on an entry-level machine. This can make a USD $50000+ difference in the price.

Why this is important for you.

When you combine a fluence of 35 J/cm2 with a skilled therapist you will find good results for the first two treatments and less on the third treatment. Thereafter, the results will plateau, and you will have an unhappy client by session five.

A machine with a fluence of 100 j/cm2 or more will allow a skilled therapist to reach an average of 80% hair reduction on most clients suitable for laser hair removal. This will usually be done in 8 sessions.

It is not recommended that you buy a diode laser with a fluence of less than 60 J/cm2. You will not be able to compete in the marketplace with such a machine.

Pulse duration

You need a long pulse for hair removal. The Thermal Relaxation Time (TXT) for a hair range between 10 ms and 100 ms, depending on the individual hair. And the Thermal Damage Time (TDT) range between 200 ms and 400 ms.

This means that you will have no permanent hair removal with a pulse length of less than 10 ms. Ideally you want to be able to stretch you pulse over 400 ms.

A longer pulse ensures that you have a good result on the widest range of hair, and it also allows for a gentler effect on the epidermis.

Keep in mind that you will still have shedding with a very short pulse duration. But shedding in itself is no indication of permanent hair removal.

Support

The training, as well as technical support you get from your supplier is very import to the success of your laser clinic.

Part of the price you pay for dealing with a local supplier is a guarantee to have access to someone you can deal with when the need arises. In your language and familiar with your circumstances.

Get referrals when you deal with a local supplier and take the time to contact the persons referred. Do not think that they will only say good things. Most people will give you honest answers on your questions. An established distributor will have at least one person who have bought from them a second time. If you only get referrals for once-off buyers only, it should ring a warning-bell.

If you import your machine yourself from China, be prepared to get very little support. The Chinese are known for the fact that they will answer and give you exactly what you ask. Make sure there is no room for alternative interpretation in any of your communication. Do not assume that they will provide you with any additional information that you have not directly asked for, because they will not.