29/08/2026
Why Were Fractional Lasers So Revolutionary?
From “Improving” the Skin to “Replacing” It
There are countless treatments in aesthetic medicine designed to lighten pigmentation, reduce redness, or make pores less visible.
But that is not what made fractional lasers revolutionary.
The real breakthrough lies somewhere much deeper.
Instead of simply making the skin we already have a little better, the idea was to deliberately destroy tiny portions of aged skin and stimulate the body to rebuild them as new tissue.
In other words, it is not simply “repair.”
It is replacement.
Think of an old house.
If the walls are slightly dirty, you can clean them. If there is a small scratch, you can repair it.
But if you really want to restore a wall that has deteriorated over many years, it may be better to strip away the damaged material and rebuild it with something new.
Skin works in a somewhat similar way.
When skin changes as a result of ultraviolet exposure and aging, it is not simply a matter of discoloration. The structure of the epidermis changes, and so does the collagen architecture in the dermis.
Many conventional aesthetic lasers have traditionally targeted a specific “problem”: pigment for spots, blood vessels for redness, and so on.
Fractional lasers changed that concept one step further.
They create countless microscopic treatment zones within the skin, each narrower than a human hair.
They do not destroy the entire surface of the skin.
Instead, treated areas and intact, healthy skin are left side by side.
That was the breakthrough.
If you ablate the entire surface, you can certainly achieve extensive resurfacing. But recovery takes longer, and redness and inflammation can be much more pronounced.
So the concept was turned upside down.
You don't have to replace everything at once.
You can create tiny areas of controlled injury, and allow the surrounding healthy skin to help drive the healing process.
In other words:
You create countless tiny “construction sites” inside aged skin, where the tissue can begin the process of rebuilding itself.
And then you harness the body's own wound-healing capacity.
The epidermis regenerates, while collagen in the dermis undergoes remodeling.
The laser itself does not create new skin.
The laser simply tells the skin:
“Rebuild this area.”
The body does the real work afterward.
I find this aspect particularly fascinating.
When people think of aesthetic medicine, they often imagine adding something.
Injecting hyaluronic acid.
Inserting threads.
Delivering drugs or other agents.
Fractional lasers work in the opposite direction.
First, you create a very small, controlled injury.
Then you let the body rebuild itself.
It is a treatment that makes use of both destruction and regeneration.
Of course, this does not mean that the entire skin of the face is literally exchanged for brand-new skin.
More precisely, I think of it as a treatment in which small portions of the skin are gradually replaced, over and over again, while the tissue as a whole is progressively remodeled.
That is why fractional lasers are not simply machines for “making the skin look better.”
They helped move aesthetic medicine
from treating the surface to reconstructing the tissue itself.
So, are all fractional lasers basically the same?
This is where things get interesting.
There are many different fractional laser systems around the world.
CO₂ lasers.
Er lasers.
1927 nm thulium-based lasers.
2910 nm fiber lasers.
And hybrid systems such as HALO, which combine multiple wavelengths.
So what is the difference?
I think it is more important to look at what each system actually does inside the skin than to focus on the name of the machine.
After all, the interaction between laser light and skin is ultimately a matter of physics.
For resurfacing lasers, one of the major targets is water.
Skin contains a great deal of water.
And when the wavelength changes, the way that light is absorbed by water changes as well.
As a result, the following all change:
How deeply the light penetrates.
How much tissue is ablated.
And how much residual heat remains in the tissue.
Once you understand this, the individual personalities of different lasers become much easier to appreciate.
CO₂ Lasers — Ablation Plus Residual Heat
The 10,600 nm CO₂ laser is strongly absorbed by water in the skin and vaporizes tissue.
In other words, it is an ablative laser.
But the defining characteristic of CO₂ is not simply that it removes tissue.
It also leaves a relatively large zone of residual thermal injury around the ablated area.
That heat causes collagen contraction and promotes subsequent tissue remodeling.
This is why CO₂ lasers remain extremely powerful tools for deep wrinkles, acne scars, and other conditions requiring substantial resurfacing.
The downside is equally clear.
The greater the thermal effect, the greater the potential for downtime, prolonged erythema, inflammation, and post-inflammatory hyperpigmentation.
So if I had to describe CO₂ in one phrase, it would be:
“Ablation plus residual heat.”
It is powerful.
And that is precisely why it requires careful handling.
Er 2940 nm — Precise, Clean Ablation
The 2940 nm Er laser also targets water.
But it is absorbed by water even more strongly than CO₂, meaning that the energy is deposited very close to the skin surface.
As a result, tissue can be vaporized extremely efficiently.
In other words:
It is a laser that can ablate tissue with remarkable precision and cleanliness.
An interesting point here is that strong absorption by water does not necessarily mean “extremely hot.”
Because the energy can be consumed so rapidly at the target site, certain settings can minimize unnecessary residual heat in the surrounding tissue.
That is one of the major differences from CO₂.
However, even with Er, thermal effects can be deliberately increased by using longer pulse durations.
So it would also be inaccurate to simply say:
“Er produces little heat.”
Laser behavior is not determined by wavelength alone.
1927 nm — Gently Remodeling the More Superficial Layers
The 1927 nm laser is one of the representative wavelengths used for non-ablative fractional treatment.
Rather than extensively removing tissue, it creates microscopic zones of thermal injury in the epidermis and superficial dermis.
That makes it particularly useful for conditions such as:
Pigmentation and uneven skin tone.
Photodamage.
And overall skin quality.
Unlike CO₂ or Er, which can be thought of as literally creating microscopic channels through tissue by ablation, 1927 nm treatment is more like placing countless small thermal stimuli in the superficial skin and gradually encouraging renewal.
Its ability to promote skin renewal while keeping downtime relatively limited is what makes this wavelength so interesting.
2910 nm — Precisely Controlling How Tissue Is Ablated
One of the more interesting recent developments is the 2910 nm fiber laser.
Its wavelength is very close to that of the 2940 nm Er laser.
So you might assume they are essentially the same.
But it is not quite that simple.
With lasers, skin response depends not only on wavelength, but also on:
How quickly the energy is delivered.
How much energy is delivered.
How frequently it is delivered.
And over what area.
A 2910 nm fiber laser can deliver small amounts of energy at high speed and with highly controlled spatial distribution.
In other words, the concept is not simply to control how deeply tissue is ablated, but to precisely control how the ablation itself is performed.
You can treat superficially and gently, or change the parameters to achieve a deeper treatment.
It feels like laser engineering has moved to another level.
HALO — Don't Ask One Laser to Do Everything
The concept behind HALO is even more interesting.
Instead of asking a single wavelength to perform every task, it combines wavelengths that are better suited to different depths.
A 1470 nm wavelength creates thermal coagulation deeper in the tissue, while 2940 nm is used for superficial ablation.
In other words:
Treat the deeper layers thermally. Ablate the superficial layers. Let each wavelength do what it does best.
More recently, approaches combining 1927 nm as well have introduced the idea of treatment across three wavelength domains.
Deep layers.
Superficial layers.
The surface.
Each can be designed separately.
At this point, laser treatment begins to resemble something closer to three-dimensional tissue engineering than conventional resurfacing.
So Which Laser Is the Best?
This is a question I am often asked by patients.
But I don't think the question itself is particularly meaningful.
CO₂ is the strongest, so it must be the best.
Er produces less residual heat, so it must be the best.
The newer 2910 nm technology must be the best.
HALO combines multiple wavelengths, so it must be the best.
It simply does not work that way.
The important question is:
What are we trying to treat?
Deep acne scars require sufficient depth.
For uneven pigmentation, the superficial layers may be the primary target.
For fine wrinkles, we may want dermal remodeling.
And with Asian skin, the risk of post-inflammatory hyperpigmentation must also be taken into account.
The choice will also be different for someone who needs to return to work the next day and someone who can afford to take a week off.
So the real question is not:
“Which machine is the best?”
It is:
How deep should the treatment go, how much injury should be created, and at what density?
Laser treatment is a form of medicine in which we design the biological response we want to create inside the skin by combining parameters such as:
Wavelength.
Energy.
Pulse duration.
Depth.
Treatment density.
Spot size.
Twenty years ago, the revolution brought about by fractional lasers was the discovery that:
“We don't have to destroy the entire skin surface.”
And now we are moving beyond that.
How deep?
How wide?
At what density?
How much residual heat should remain?
How much tissue should be ablated?
We are increasingly able to design all of these variables.
I don't think the future of aesthetic lasers lies simply in developing more powerful lasers.
Rather, it lies in creating the right amount of injury, in the right place, and only where it is needed.
The goal is to generate the maximum regenerative and remodeling response with the minimum necessary injury.
Over the past two decades, aesthetic lasers have evolved
from machines that “burn the skin” into precision tools for tissue engineering—designed to rebuild the skin itself.
That, I believe, is how far the field has come.
