The wavelength determines what a laser targets in the skin: melanin, haemoglobin or water, and how deep the light penetrates. This page goes through the most important wavelengths one by one, from 532 nm through 755, 808, 940, 1064, 1320, 1470, 1550 and 1927 nm to 10,600 nm, and also explains broadband light from 400 to 800 nm.
For each wavelength you will find out what it is used for and which SIACSKIN device offers it: from the DEWEON 4LD and the AlexDUAL UFO through the PICOLO lasers and the TULIX to the FRACO CO2 XL and the DERMAFORCE BBL PRO.
Why does the wavelength determine what a laser hits in the skin?
Each target structure in the skin strongly absorbs only certain wavelengths, and heat is generated only where light is absorbed. The three important targets are melanin in hair and pigment spots, haemoglobin in the vessels and water throughout the tissue. Melanin absorbs short-wavelength light most strongly and less and less as the wavelength increases. Haemoglobin has peaks in the blue, green and yellow range. Water only becomes the main absorber in the infrared from about 1400 nm. Whoever chooses the wavelength therefore chooses the target.
That is why SIACSKIN devices cover different ranges: the DEWEON 4LD with 755 to 1064 nm for melanin in the hair, the DERMAFORCE BBL PRO with 400 to 800 nm for pigment and vessels, the FRACO CO2 XL with 10,600 nm for water.
How are wavelength and penetration depth in the skin related?
In the visible and near-infrared range, the rule is: the longer the wavelength, the deeper the light penetrates, until water intercepts the energy. Short-wavelength light is strongly scattered in tissue and absorbed by melanin and haemoglobin, so green light at 532 nm penetrates only fractions of a millimetre. Between about 700 and 1100 nm, scattering and absorption are low, and here light reaches several millimetres and thus the hair root. Above about 1400 nm this reverses: water absorbs the energy, and the depth falls to a few hundredths of a millimetre at 10,600 nm.
The AlexDUAL UFO uses this window with 755 and 1064 nm. The TULIX deliberately works more superficially with 1550 and 1927 nm, in the dermis and epidermis.
The 532 nm wavelength is used for red and orange tattoo inks and for superficial pigment spots. Green light is absorbed very strongly by red ink pigments, by melanin and by haemoglobin, but penetrates only shallowly. It therefore acts where the target sits in or just below the epidermis, for example with age spots and freckles. The strong absorption by melanin is also the limit: on dark or tanned skin the risk of lighter or darker patches rises, and dosing is cautious there or 1064 nm is used instead.
The PICOLO XL and the PICOLO S offer 532 nm alongside 755, 1064 and 1320 nm. The PICOLO L offers the wavelength with up to 500 mJ for red, orange and light colours.
What does the 755 nm wavelength do for hair removal, pigment and tattoo inks?
The 755 nm wavelength targets melanin particularly strongly: it is absorbed very well by hair pigment and therefore also picks up finer and dark blonde hairs, as long as they contain enough pigment. Because the melanin of the epidermis reacts strongly too, it is intended above all for fair skin types. In very short pulses, the same wavelength is used for pigment treatment and for removing green and blue tattoo inks, which barely absorb 1064 nm. It is generated in two ways: in the alexandrite crystal or in laser diodes.
SIACSKIN offers both. The AlexDUAL UFO generates 755 nm in the alexandrite crystal, and the DEWEON 4LD has 755 nm as one of four diode wavelengths. For tattoo and pigment, the PICOLO XL offers 755 nm in the Honeycomb and rectangular variants.
Why is 808 nm considered the standard wavelength for a diode laser?
The 808 nm wavelength is considered the standard because it offers the best compromise between effect on the hair, penetration depth and protection of the epidermis. Melanin still absorbs it well, but more weakly than 755 nm, so the epidermis is stressed less. At the same time, the light reaches deep enough to get to the hair root on the legs, underarms or back. Then there is the technology: laser diodes for this range are efficient, durable and allow high repetition rates for large areas. For very fair skin with fine hairs and for dark skin, there are more suitable wavelengths in each case, which is why modern devices combine several.
The DEWEON 4LD works with 808 nm and adds 755, 940 and 1064 nm, at up to 30 Hz and 6000 W total power.
What distinguishes the 940 nm and 980 nm wavelengths physically?
Both lie close together in the near infrared, but at 980 nm water absorbs markedly more energy than at 940 nm. At 940 nm, melanin absorbs only moderately, the epidermis is spared, and the blood pigment haemoglobin absorbs part of the energy. In hair removal, this is the wavelength for medium to darker skin types. There is a water absorption peak at around 980 nm. As well as the blood, the light therefore heats the tissue itself more strongly, while penetration depth remains good.
The DEWEON 4LD has 940 nm between 808 and 1064 nm. The SIACSKIN x Velaslift offers 980 nm alongside 450, 635 and 1470 nm. As applications of the device, SIACSKIN names vascular lesions, thread veins and redness, among others.
Why is the 1064 nm wavelength found in so many different lasers?
The 1064 nm wavelength is so widely used because it penetrates deeply, spares the epidermis and, depending on pulse duration, can be used for very different targets. Melanin absorbs it only weakly, which makes it the safe choice for dark skin types. With long pulses in the millisecond range, it heats hair roots, including deep-seated ones. With extremely short pulses in the nanosecond or picosecond range, it shatters black and dark tattoo pigments and is the basis for the carbon peel. The same wavelength, a different pulse duration, a different effect.
At SIACSKIN you will find 1064 nm in the AlexDUAL UFO as Nd:YAG for skin types V to VI, in the DEWEON 4LD as a diode wavelength and in the PICOLO XL, PICOLO L and PICOLO S for tattoo and pigment.
What is the 1320 nm wavelength used for in an Nd:YAG laser?
The 1320 nm wavelength is used for gentle skin rejuvenation, not for pigment or tattoo inks. At this wavelength melanin hardly plays a role any more; instead, the water in the tissue absorbs the energy moderately strongly. The light heats the upper dermis over a wide area without injuring the epidermis. This mild heat is regarded as a stimulus for collagen formation and is used for the complexion, pores and a fresher skin tone. It differs from the carbon peel at 1064 nm in that no carbon is needed as a target: the skin's own water absorbs the energy.
The PICOLO XL and the PICOLO S offer 1320 nm alongside 532, 755 and 1064 nm. SIACSKIN explicitly names skin rejuvenation and pores as applications of the PICOLO XL.
Light at 1470 nm is strongly absorbed by water and therefore heats the tissue over a short distance, largely independently of melanin and skin colour. The absorption by water here is many times higher than at 980 or 1064 nm. The energy is not distributed over millimetres but converted into heat in a thin layer. Even with little power, this produces tightly confined heating or coagulation, and the surrounding tissue is spared. What exactly is treated with it depends on the applicator, power and specialty.
At SIACSKIN, the SIACSKIN x Velaslift offers 1470 nm, together with 450, 635 and 980 nm at 57 W. For the device, SIACSKIN names vascular lesions, thread veins, redness, acne and skin rejuvenation, as well as medical applications depending on specialty and approval.
Why does a 1550 nm laser not ablate skin even though it targets water?
Because water absorbs 1550 nm only moderately, the energy is spread over a greater depth and heats the tissue without vaporising it. For ablation, water must suddenly exceed boiling point. This happens at 10,600 nm, where the energy is trapped in an extremely thin layer. At 1550 nm, the same energy reaches more than a millimetre into the dermis and creates fine columns of coagulated tissue there. The stratum corneum is preserved, and the skin is red afterwards but intact. The remodelling into new collagen takes place over weeks.
The TULIX from SIACSKIN uses 1550 nm erbium glass for the dermis and combines it with 1927 nm for the epidermis. The usual course is 3 to 5 sessions at intervals of about 4 weeks.
For which skin problems is 1927 nm the right wavelength and where is it not enough?
The 1927 nm wavelength is right for everything located in the epidermis: pigment spots, sun damage, a dull complexion, fine irregularities. Water absorbs the wavelength so strongly that its effect ends after about 0.2 mm. There it renews the epidermis evenly and largely independently of skin colour. It is not sufficient for problems at depth: sunken acne scars, pronounced wrinkles and lax skin need a wavelength that reaches the dermis, or another method. Hairs, tattoos and vessels are also not targets for 1927 nm.
In the TULIX, 1927 nm thulium takes care of the surface and 1550 nm the depth. For intensive resurfacing, the FRACO CO2 XL is available, and for tightening the EUPHEUS M8.
Why does the 10,600 nm wavelength of the CO2 laser ablate tissue?
The 10,600 nm wavelength ablates because water absorbs it extremely strongly and all the energy lands in a layer a few hundredths of a millimetre thick. The tissue water vaporises there suddenly and takes the cells with it. At the edge of the ablated site, a narrow heated zone remains that seals small vessels and contracts the collagen. This gives rise to its uses: fractional for scars, wrinkles and skin texture, and with a focused beam as a cutting tool. Skin colour plays no role in absorption, but a great one in healing.
The FRACO CO2 XL works at 10,600 nm from a 100 W RF source, with pulses of 0.1 to 100 ms. The device also comes with a Cutting-Head for surgical applications and a gynaecological applicator.
What distinguishes broadband light of 400 to 800 nm from a single laser wavelength?
Broadband light contains many wavelengths at once and thus hits several target structures in one pulse, whereas a laser emits a single wavelength and thus hits its target more precisely. In the range of 400 to 800 nm lie the absorption peaks of haemoglobin and the strong absorption by melanin. A single flash of light therefore treats brown pigment spots and red thread veins together. Filters cut off part of the spectrum and thus shift the emphasis. The price of this breadth: the energy is less targeted, and because a lot of short-wavelength light is included, the melanin of the epidermis reacts strongly too. Dark skin is therefore the limit.
The DERMAFORCE BBL PRO works with 400 to 800 nm and 9 filters, intended according to SIACSKIN for skin types I to IV. It is not a laser.
Can you change the wavelength of a laser or does each need its own source?
The wavelength is fixed by the laser medium and cannot be freely adjusted, so several wavelengths need several sources or a converter. An alexandrite crystal delivers 755 nm, an Nd:YAG crystal 1064 nm, CO2 gas 10,600 nm. Three routes lead to more choice. Devices combine different sources, such as laser diodes for several wavelengths. A frequency-doubling crystal turns 1064 nm into green light at 532 nm. And dye attachments convert green light into yellow or red, for difficult tattoo inks such as sky blue and green.
The DEWEON 4LD thus combines 755, 808, 940 and 1064 nm. The PICOLO XL offers 532, 755, 1064 and 1320 nm and can optionally be extended with a Dye-Head at 585 and 650 nm.
How do I choose the right wavelength before a treatment?
You proceed in three steps: determine the target, estimate the depth, check the skin type. The target fixes the range: melanin for hair and pigment, haemoglobin for vessels, water for skin renewal. The depth narrows it further: superficial targets call for shorter wavelengths, deep ones for longer. The skin type sets the safety limit: the darker the skin, the longer the wavelength for all treatments that target melanin. A test patch and a look at the skin reaction then follow, before the whole area is treated.
For hair removal, the DEWEON 4LD takes the choice off your hands: its AI skin analyser selects wavelength and energy automatically. On the AlexDUAL UFO, 755 nm is available for fair and 1064 nm for dark skin types. The SIACSKIN method comparison gives an overview.
