This introduction to lasers in cosmetic surgery is an excerpt taken from a live lecture given by Warren B. Seiler III, MD, DABLS, at the Inaugural ALSC Symposium.  (This excerpt is included in the interest of educating others and sharing knowledge with practitioners of various specialties, which is the mission of the ALSC and its educational and conference offerings).

Introduction to Laser Cosmetic Surgery

Although both ablative and non-ablative lasers are used to treat sun damage, lines, wrinkles, and acne scars, they are vastly different. Ablative lasers remove tissue by vaporizing it.  Non-ablative lasers use different wavelengths of light to affect various targets, creating non-vaporized channels of heated tissue.

The traditional CO2 laser was associated with an aggressive treatment; the risk involved with it was the possibility of scarring and hypo- or hyper-pigmentation. Newer, fractionated CO2 technology is significantly safer. The cosmetic outcome of fractionated CO2 laser treatment is great and there is much less downtime for the patient than with the traditional CO2 laser.

Ablative vs Non-Ablative Lasers

There is a significant difference between ablative and non-ablative lasers. Ablative lasers target water in soft tissue to vaporize (remove) tissue. Non-ablative lasers target water in soft tissue without vaporization; such treatment is intended to channel heat-induced injury to various depths in order to stimulate collagen production and skin tightening, reduce pigment, and address acne and acne scars. There is a lot less downtime with non-ablative laser treatments because the tissue is not removed, but instead, it is heated to different depths (depending on different wavelengths).

The CO2 laser is much safer in lighter skin. The fractionated non-ablative devices, however, are generally safe for both light and dark skin with the appropriate device and substantial experience in treating darker skin patients. Prior to the introduction of the newer non-ablative technology in the last 10 years, when only traditional CO2 lasers were available for facial resurfacing, clinicians couldn’t treat even some of the darker Caucasian patients, and could not treat non-Caucasian patients, nor could they treat “non-face” areas like the neck, etc.

The Power of Laser Pulse

There are different types of pulsing for CO2 lasers. In the cosmetic world, there is a newer technology called UltraPulse (which consists of a very short pulse duration with high pulse power and very high fluence), which is even faster than SuperPulse (medium pulse duration with medium pulse power). A good device has less than a millisecond pulse width which means it is incredibly fast-firing. Such a fast-firing device penetrates target tissue deeper with a lot less collateral damage. In the world of cosmetics, even a day or two less of downtime makes a huge difference for patients – where one can reduce the downtime from 7-10 days to 5-7, it is a matter of taking an extra week off work or not. SuperPulse, with its medium pulse duration and pulse power, creates slightly more collateral damage, compared to UltraPulse and more downtime. The traditional (non-pulsed) CO2 laser would not get nearly as deep for the same amount of energy and will cause a wider zone of coagulation and thermal damage.  That is something that all clinicians should consider in their cutting devices: i.e., how fast the device fires, what the different spot sizes are so that one knows that it is possible to make finer incisions and do ablative tightening.  So in the world of cosmetic surgery, it is very important to realize that there is a significant difference between various CO2 devices (i.e., some of the lower-end devices don’t have nearly as much power as high-end ones, they don’t fire as fast, and therefore they result in much longer downtime and the only way to get a stronger treatment is to simply increase the laser power, but that will lead to a more extensive downtime).

Now the new CO2 technology allows the clinician to use different handpieces: i.e., one to get deep collagen stimulation and the other – with a larger spot size – still enables ablative resurfacing, where the epidermis is removed to achieve superficial tightening and pigment reduction but laser energy does not penetrate as deeply, so the downtime is shorter than that after the traditional operative COprocedure.

Comparing Ablative CO2 and Erbium Lasers

A rising topic in cosmetic surgery is CO2 (10,600 nm) vs ablative erbium (2,940 nm). Both wavelengths are ablative, target water, and vaporize/remove tissue; both are used to treat sun damage/pigmentation, lines, wrinkles, acne scars.

Ablative erbium: Although both erbium and CO2 wavelengths target water (their main chromophore), the absorption coefficient of the erbium 2940 nm is much greater, therefore treatment produces a much more superficial ablation. Therefore, one has to use more energy to get as deep as CO2, and this leads to more downtime, because there is so much heat involved, but you still don’t get near the depth. So, for a patient treated with ablative erbium and one treated with ablative fractional CO2, results are similar in the three-month range, but where CO2 truly excels is the one, two or three years down the road where the skin is really remodeled, collagen is regenerated and there is a much nicer collagen “brick wall”. (Bottom line: erbium potentially causes more downtime, less result, less longevity; it creates more superficial peel (unless energy is increased, which increases downtime).

Again, CO2 laser treatment, if fractional, leaves some epidermis, while fully ablative erbium may not get nearly as deep and may completely remove the epidermis, but it doesn’t produce deeper collagen stimulation.

Laser Wavelength Absorption

It is important to see that CO2 is well absorbed in water. Although it is well absorbed in water superficially, enough energy is left over to penetrate deep and target water deeper in the dermis.

The ablative erbium wavelengths in the 2,940 – 2,950 nm range are shown high on the water absorption curve so that absorption of water is very high superficially, but there is less depth of penetration.

Diodes are low on the absorption curve, in the 800 nm range. Nd:YAG wavelength has very low water absorption. That’s why diodes are using more heat than they are actually using the wavelength of a laser (that is to say, they do surgery thermally, similar to electrocautery, rather than photo-thermally, like surgical lasers).

New Fractionated Technology

“Fractional” refers to a fraction of the skin. Sections of the epidermis are left alone, in contrast to the older continuous wave CO2 technology, where the epidermis was completely wiped off before the surgeon used the laser to fire again on the dermis. With fractionated technology – depending on the density used – small islands of the epidermis are left untouched. Histologically it is much better for the epidermis to regenerate itself than try to grow new epidermal cells from the native cells that are coming up through the dermis. Therefore, healing is much better following fractionated CO2 laser treatment.

In high-end fractionated CO2 laser technology (instead of using overlapping back and forth strokes, like was done with older CO2 lasers in the past), one uses a computer-generated scanner – it generates a pattern so quickly that there is no lining up of the hot and cold areas (so-called “tiger striping”), so every time before the clinician moves from one spot or square to the next, she or he has already uniformly heated and started to let that area cool.  With older continuous wave CO2 technology there was a lot of lining up of more and less heated passes, or “tiger striping,” and more risk of damaging the skin and normal melanocytes.

“Tiger striping” occurred when the older continuous-wave CO2 device fired back and forth, by the clinician moved to the next square or shape, there could have a lot of lining up of heat. With that technology, the clinician had to be incredibly precise with lining up spot sizes and laser strokes; and now one can do a full face in only 8 to 10 minutes, where back then, even in good hands, it would take one 20 minutes to line laser passes up.

Choosing an Ablative CO2 Laser

With aggressive ablative CO2 treatment (95% density after the deep pass), Valtrex, clindamycin, and Diflucan are used. With non-ablative Fraxel, only Valtrex is needed.

For a patient who needs more of a traditional operative CO2 result, what I call the “CO2 split” may be utilized. First, only the deep treatment is performed (which is more of a collagen stimulator, with a short downtime – 4-5 days – using only 15% pulse density with a smaller spot size). Then the patient returns a month later for a more aggressive 95 to 100% peel. Sometimes during this return visit the clinician scrubs and debrides the ablated tissue, especially in the perioral area, and then makes another laser pass. But the risk [of striping] is much less with this approach because of the computer-generated scanner. The spot size is also smaller than older CO2 devices, so although, technically, a fully ablative pass is performed, the way that the laser fires does not cause so much skin heat bulking.  Therapy with platelet-rich plasma and medical-grade skincare makes a significant difference in healing.

It is very important to understand one’s own device. In the cosmetic skin world, numerous laser devices are sold. There is a lot more competition than in some of the other medical fields. In my opinion, I prefer the Lumenis DeepFX and ActiveFX (shown on the slide) – what sets it apart from other CO2 laser devices is the short, 1-millisecond pulse width. This pulse width allows the clinician to produce deep narrow channels to deliver deep heat without causing much collateral damage. With some less expensive devices that have much lower power, the only way to get deep is to really increase the power, which results in a wider thermal damage zone.

CompanyProductWavelengthSpot SizeTreatment AreaMax DepthDensitySpeedPowerMax Energy (mj)Dwell Time at Max Energy *Max Energy @ Safe Dwell Time **
LumenisDeepFX10,60012010×10any5-45%600 hz240 W240 mj1 ms240 mj
LumenisActiveFX10,60013009 x 930055-100%600 hz240 W240 mj1 ms240 mj
ReliantFraxel re:pair10,60012015 x 15160010-70%2100 MTZ/sec40 W70 mj1.75 ms40 mj
CynosureAffirm10,60035015 x 1550060-98%5-100hz30 WUnknownUp to 20 ms30 mj
AlmaPixel CO210,60035010 x 10Unknown15-20%500 hz30 W30 mj
LaseringMixto SX10,60030020 x 2050020-100%30 W30 mj
DekaSmartXide DOT10,60035015 x 1550060-98%5-100 hz30 WUp to 80 ms30 mj
MedArtMedArt FrX10,60030010 x 1016607-20%0.3 – 100 Hz15 WUp to 1000 ms15 mj
LutroniceCO210,600100014 x 1410 – 200 Hz30W240 mj8 ms30 mj

Non-Ablative Fraxel

laser thermal injury

Figure 5: Non-ablative fraxel laser (zones of thermal injury). Copyright by Seiler Skin

Non-ablative Fraxel: It is a fractionated laser used in the 1550 nm wavelength range for targeting water and resulting in collagen stimulation. The clinician can get deep with this device without removing tissue, this is non-ablative. Because the 1550 nm wavelength is not absorbed much in pigment, it doesn’t really help with sun damage removal and other pigmentation issues; so some of the newer devices have a thulium laser – a 1927 nm wavelength that is also absorbed in water, but has a great pigment clearance. The two different wavelengths are combined in a single device, but with this Fraxel device, downtime is in the 2 to 3 day range. Fraxel treatment still results in good skin tightening, but the clinician should know when to use a non-ablative vs ablative device. The image shows that, as opposed to actually ablating columns of tissue, non-ablative devices just translate heat to different chromophores at different depths, depending on the settings used on the device.

Laser Wavelengths for Pigment Targets

Q-switched Nd:YAG lasers (that produce 1064/532 nm wavelengths) are another type of laser used in cosmetic laser surgery. Q-switch lasers are also safer and utilized for pigmentation issues in darker skin patients, whereas other lasers may be too dangerous because of their naturally darker skin. Q-switched lasers can also be used for tattoo removal.  The 1064 nm wavelength is utilized for flat spots, while the 532 nm wavelength is reserved for raised lesions. Q-switched lasers are potentially less aggressive than IPL devices and are excellent for “difficult pigment” (i.e., melasma, PIH, darker skin). Q-switched laser treatment results in minimal downtime and post-op discomfort.

Lamprobe: For small vascular lesions on the face there is a great device called Lamprobe, which is a non-laser, radiofrequency device. It only costs about six thousand dollars and utilizes different size disposable probes (that cost only about a dollar each). Lamprobe is great for tracing small spider veins and telangiectasias, skin tags, benign moles, Ak/SKs, acne, milia, and angiomas. The downtime and post-treatment discomfort is minimal.

Laser Wavelengths for Vascular Targets

One of the lasers used for vascular targets is Nd:YAG (1064 nm wavelength) with a sapphire tip that slightly defocuses the beam so that it is still high powered, but does not incise tissue. This device is great for larger vessels on the legs (up to approximately 1-2 mm), larger angiomas/PWS. So instead of doing more invasive sclerotherapy (which is reserved for some of the larger vessels), the clinician can use a non-invasive laser for spider vein treatments on the body without much downtime; and usually, one or two treatments are enough to resolve the vascularity issue. (Facial vessels, however, are better and safer treated with IPL and Lamprobe devices.)

Laser Wavelengths for Hair Reduction

Alexandrite laser (755 nm wavelength)

Ruby lasers were originally used for hair removal. But they were too aggressive and could damage skin. Approximately two decades ago Alexandrite lasers came out, but could only treat fair-skinned patients (Caucasian, skin types 1-3) because the 755 nm wavelength is heavily absorbed in the melanin curve at the top (this is important for hair reduction as it ensures enough absorption by the pigment to kill the hair follicle, but not so much to hurt the normal pigment). Therefore, this wavelength was not good for non-Caucasian patients.

Diode laser (810 nm wavelength)

Diodes are much better suited for darker-skinned patients than Alexandrite (in fact, they work well for all skin and hair types with the right device and clinician experience). The laser is used in a non-cutting mode and the laser beam is slightly defocused. With the more sophisticated diodes, the time between pulses can be increased (all the way up to 100-400 msec), so that the skin is not punched so quickly with acute heat. So, in a dark-skinned patient, the treatment will preserve their normal pigment, but there can still be a good translation of the heat into the target hair, sufficient to achieve follicle destruction and permanent hair reduction. Some of the less sophisticated devices do not permanently destroy hair follicles and two years after treatment hair can regrow. Another possibility of using a lower-end device or using the wrong settings is treatment may depigment target hair, and when the patient returns to the clinician – s/he still has the unwanted hair, but the pigment remaining from the previous unsuccessful treatments is insufficient for successful re-treatment with a higher quality diode device (permanent hair reduction).

Nd:YAG (1064 nm wavelength)

This wavelength has been the gold standard in the past for treating non-Caucasian skin because this wavelength avoids some normal pigment in the skin. But Nd:YAGs are more painful than diodes and take a few treatments more than diode treatments.

Cosmetic Laser Surgery Cases

Fractional Ablative CO2 Laser Surgery

With traditional CO2 the clinician would never treat “off-face”, so one would never treat the neck and the chest. So the clinician could give the patient a so-called “floating head” (when a patient had sun damage and wrinkles, may or may not have had major facial surgery, traditional CO2 treatment would produce nice tightening, sometimes even too much lightening of the epidermis on the facial skin and the clinician would stop on the neck or the jawline, but she or he could not do the neck and chest). Generally, a patient had tons of sun damage and wrinkling and poikiloderma on their chest, but treating that with a laser was not an option. With the fractional CO2 laser technology one can treat the neck and chest, as well as the face. The downtime is usually two to three weeks on the neck and chest, compared to a week on the face. As can be seen in the photo taken at one week, the patient is able to cover the redness on her face with a little bit of medical-grade makeup. The neck is still fairly red, but the patient is able to cover it up with clothing and hair. And already at this point (one week post-op) she can return to work and to normal life.

Acne CO2 Laser Treatment

This acne patient had received a CO2 laser treatment with a good outcome.

Hemangioma on the Scalp Laser Treatment

Some fractionated CO2 lasers come with surgical handpieces with several different spot sizes that can be used to remove various lesions. This is a large hemangioma that was removed from the patient’s scalp.

Hemangioma on Chest Laser Treatment

This was a one-time treatment with minimal downtime. The procedure typically results in a nice bit of skin tightening even with surgical CO2 handpieces. The laser beam can be slightly de-focused to cauterize the wound and get the wound surface to shrink up. And because of that stimulation, the treatment results in good collagen remodeling, skin grows back. The slide shows that even though there is some lesion pigment left, the patient was satisfied with the result. The clinician intended to do more: he wanted to get rid of pigmentation, but the patient was happy with just having that large lesion removed.

Facial Mole / Tumor Laser Excision

This is something that traditionally would have to be excised, and it is useful for a cosmetic surgeon to have a good relationship with several dermatologists in town in case there is some sort of malignancy. Therefore, the clinician should always have these things checked or biopsied before removing them.

Rhinophyma Laser Ablation

A gentleman with rhinophyma and some vascular issue under his right eye – it is noticeable that a pretty good skin tightening was achieved under the eye without doing a lower blepharoplasty. This is the result of four treatments. When treating the rhinophyma the tissue was ablated in layers, then scrubbed off, then another pass was performed.

Pigmentation around eye (Nevus) Laser Treatment

This is the case still in progress. This little girl had a congenital compound nevus that encased the upper and lower lid, and prior to the surgical excision that was done by a plastic surgeon when she was 5, the nevus was almost all the way to her hairline. The plastic surgeon surgically revised it but didn’t feel comfortable going any farther. So, the mother found a clinic that utilized fractional CO2 laser technology.

This is the patient four years after the initial plastic surgery. A pretty good amount of nevus tissue is visible. The biopsy confirmed that it was a congenital nevus, so it was something safe for the COlaser clinician to remove with ablation. And then a much more aggressive COlaser treatment was performed. Technically the laser was not fractional, because the clinician turned the density all the way up and performed several passes.  This was more of a type of CO2 that would have been used in the OR in the past. Where a full pass is done, a full debridement is done; then the clinician keeps passing again until s/he feels the treatment is deep enough. It is not possible to know exactly how deep the nevus tissue is in different areas, so the clinician doesn’t know how much resolution is possible to get with such a case.

Just topical numbing was done for the patient, for about an hour and a half to really allow the laser beam to penetrate deeply without much discomfort. The clinician used a small insulin syringe with some lidocaine injections, and the patient didn’t feel any pain or discomfort during the procedure.

The patient was excited to undergo CO2 laser treatment to get rid of the nevus. And she was very realistic. She didn’t want the nevus completely gone but said she would be happy to have it lightened a little bit. So, you can see – pretty significant downtime. Her eye was swollen shut for the first two days. She was able to open it on day 3.

And this is this past week. She is doing a lot better. Still a little bit of erythema, but there was a great resolution in pigment. I did three full passes, so we literally were just scrubbing the nevus off. I mean it’s really cool clinically to actually see it done. But I think she will get a great result. I think there will be a little bit of pigment left over, on her lower lid, and maybe a little bit on her upper lid, but I am really hoping that she is going to be fully happy with that.

Sun Damage and Melasma Non-Ablative Fraxel Laser Treatment

Here is a before and after picture of a younger female patient. Prior to her treatment, she had significant sun damage and melasma.

Treatment for pigment and vascularity issues

In current practice, pigment is much easier to treat than before, especially with Intense Pulse Light (IPL) devices. IPL is a device that uses a flash lamp instead of a laser, so it is not a true laser.  IPL starts in the 400-1400-nanometer wavelength range. The more sophisticated devices come with different cutoff filters. For instance, in order to go deeper with the longer wavelengths, or to target more vascular lesions, instead of more superficial pigment, a different color of light is used to target different types of pigment. Understanding the color wheel is critical. For example, when targeting brown, the clinician uses the wavelength in the yellow to green range; when targeting red, one has to use yellow light or something darker, in the near-infrared range. The more sophisticated IPL devices have filters that cut off the shorter wavelength and enable the clinician to utilize longer wavelengths to treat different types of pigment at various depths. One IPL device can treat numerous conditions. For example, IPL is great for sun damage, with minimal downtime. Patients can wear makeup the night of their IPL procedure. The entire body can be treated with IPL (unlike with older devices, where one could not treat both the face and body). IPL does not remove tissue, so it is not used for any lesions that are raised or palpable. IPL may be superior now compared with what traditionally was the standard — the pulsed dye laser. Pulsed dye lasers are in the 585 – 595 nm wavelength range; they result in much more downtime than IPL treatment and produce a lot of purpura. There is a notable amount of bleeding with the pulsed dye devices usually. In contrast, IPL may take an extra treatment, but it is very safe, with very minimal downtime. There are many other wavelengths that will target pigment.

IPL Treatment

Before and after a single IPL treatment. A nice reduction in pigment is noticeable. This patient can wear makeup the night of the treatment, which proves that there was practically no downtime.

Vascularity of the Face Laser Treatment

Patient treated for significant vascularity on the face (single treatment).

Disclaimer: This article is for informational purposes only, and does not replace the need for individual consultations with a physician. The American Laser Study Club (ALSC) does not engage in the practice of medicine, endorse any particular commercial products, doctors, surgeons, medications, treatment, or techniques. The opinions expressed in this article are those of Dr. Seiler and do not necessarily reflect the views of the ALSC.



  1. Vitruk P. Oral soft tissue laser ablative and coagulative efficiencies spectra. Implant Practice US. 2014;7(6):19.

About the Author

Photo of Warren B. Seiler, III

Warren B. Seiler, III, MD
Faculty of the American Laser Study Club
Honorary Member of the American Laser Study Club

Cosmetic Surgeon
Seiler Skin Cosmetic Laser & Aesthetics Center
Birmingham, AL, US