Nonablative Laser Skin Rejuvenation –
Introduction And Overview
Non-ablative laser systems target only the dermis, leaving the epidermis intact. The results are not as effective as with ablative laser resurfacing but the excellent safety profile and rapid recovery post-treatment have made these systems popular. These systems have been divided into 3 main groups, infrared lasers, visible light lasers (VLL), the pulsed dye laser (PDL). Laser can be operated in several modes. They are divided into either continuous wave mode (CW) or pulsed mode. The output of a laser may be a continuous constant-amplitude output (known as CW or continuous wave); or pulsed, by using the techniques of Q-switching, modelocking, or gain-switching. In pulsed operation, much higher peak powers can be achieved. Some types of lasers, such as pulsed dye lasers and vibronic solid-state lasers can produce light over a broad range of wavelengths; this property makes them suitable for generating extremely short pulses of light, on the order of a few femtoseconds (10-15 s). Q-switching, sometimes known as giant pulse formation, is a technique by which a laser can be made to produce a pulsed output beam. The technique allows the production of light pulses with extremely high (gigawatt) peak power, much higher than would be produced by the same laser if it were operating in a continuous wave (constant output) mode. Compared to modelocking, another technique for pulse generation with lasers, Q-switching leads to much lower pulse repetition rates, much higher pulse energies, and much longer pulse durations.
The gain medium of a laser is a material of controlled purity, size, concentration, and shape, which amplifies the beam by the process of stimulated emission. It can be of any state: gas, liquid, solid or plasma. Examples of active laser media include:
- Certain crystals
- rare-earth ions : e.g. neodymium (Nd), ytterbium (Yb), or erbium (Er)
- transition metal ions (titanium or chromium); most often yttrium aluminum garnet (YAG), yttrium orthovanadate (YVO4),
- gemstone e.g. sapphire (Al2O3), alexandrite, ruby
- Glasses, e.g. silicate or phosphate glasses, doped with laser-active ions
- Gases, e.g. mixtures of helium and neon (HeNe), nitrogen, argon, carbon monoxide, carbon dioxide, or metal vapors (e.g. cooper vapor)
- Semiconductors (diode), e.g. gallium arsenide (GaAs), indium gallium arsenide (InGaAs), or gallium nitride (GaN)
- Organic Dye (usually liquid), e.g. rhodamine, fluorescein, coumarin, stilbene, umbelliferone, tetracene, malachite green, and others.
gain medium and their respective operation wavelength
Type gain medium Operation wavelength(s)
Gas Carbon dioxide laser (ablative laser) 10.6 μm, (9.4 μm)
Helium-neon laser 632.8 nm (543.5 nm, 593.9 nm, 611.8 nm, 1.1523 μm, 1.52 μm, 3.3913 μm)
Dye lasers Dye lasers 390-435 nm (stilbene), 460-515 nm (coumarin 102), 570-640 nm (rhodamine 6G), many others
Metal-vapor lasers Copper vapor laser 510.6 nm, 578.2 nm
Solid-state lasers Ruby laser 694.3 nm
alexandrite laser 755 nm
Nd:YAG laser 1064 nm, (1320 nm) ; [532 nm (green) is generated by frequency doubling Q-switch pulsed mode of operation]
Er:YAG laser (ablative laser) 2.94 μm
Neodymium glass (Nd:Glass) laser ~1062 nm (Silicate glasses), ~1054 nm (Phosphate glasses)
Erbium doped and erbium-ytterbium codoped glass lasers (Er:Glass and Er:Yb: Glass) 1530-1560 nm
Semiconductor lasers (laser diode) AlGaAs 0.63-0.9 μm
InGaAsP 1.0-2.1 μm
Vertical cavity surface emitting laser (VCSEL) 850 - 1500 nm, depending on material
Other laser parameters that can affect treatment include: pulse duration, pulse repetition rate, pulse peak power. The pulse repetition rate (or pulse repetition frequency) frep of a regular train of pulses is defined as the number of emitted pulses per second (Hz). Depending on the technique of pulse generation, typical pulse repetition rates can be in different parameter regions:
- Typical mode-locked solid-state lasers emit with pulse repetition rates between 50 MHz and a few gigahertz, but in extreme cases < 10 MHz or > 100 GHz is possible.
- Q switching of solid-state lasers typically allows repetition rates from below 1 Hz to the order of 100 kHz.
- Gain switching of semiconductor lasers can provide repetition rates from below 1 Hz to many megahertz.
- Attosecond pulse trains of finite length can be generated via high harmonic generation with repetition rates of hundreds of terahertz.
Pulse duration is another parameter that can affect laser treatment. There are actually different definitions of a pulse duration. The most frequently used definition is based on the full width at half-maximum (FWHM) of the optical power versus time. The duration of optical pulses (also called pulse width) can vary in a huge range: By modulating a continuous-wave light source, pulses with durations from some tens of picoseconds to arbitrarily high values can be generated.
- Gain switching e.g. of laser diodes leads to pulses with durations down to a few nanoseconds or even to some hundred picoseconds.
- Pulse durations from Q-switched lasers typically vary between 100 ps and hundreds of nanoseconds.
- Mode-locked lasers can generate pulses with durations between ∼ 5 fs and hundreds of picoseconds.
- High harmonic generation allows the formation of single attosecond pulses or attosecond pulse trains, with pulse durations of a few hundred attoseconds or even below 100 as.
Here is an overview on the common prefixes:
- 1 ms (millisecond) = 10−3 s
- 1 μs (microsecond) = 10−6 s
- 1 ns (nanosecond) = 10−9 s
- 1 ps (picosecond) = 10−12 s
- 1 fs (femtosecond) = 10−15 s
- 1 as (attosecond) = 10−18 s
Several green or yellow color laser on the market target mainly (superficial) facial vessels, redness, mild rosacea, uneven or hyper pigmentation. They are less consistently effective for fine lines, small wrinkles, although they may be modestly useful for photo-rejuvenation, e.g. to improve fine lines, small wrinkles and acne scars. Certain visible light lasers (VLLs), such as the pulse dye laser, have been shown to induce dermal remodeling in patients with lighter skin tones. However, the reported adverse effects of using VLLs included significant bruising and swelling that lasted up to 2 weeks. Additionally, the affinity of VLLs for melanin limited their use in darker-skinned or tanned patients.
For our purpose “Anti-Aging”, the most commonly used wavelength is infrared (or red laser) as discussed in “nonablative light therapy”. Infrared lasers and related systems utilize the wavelength range between about 1100 – 1800 nm. The relatively long wavelength allows it to penetrate relatively deeply – all the way to the lower dermis (the layer of skin where wrinkles reside) and make it useful for treating fine wrinkles and depressed scars. The infrared waves bypass the epidermis and are absorbed throughout the dermis, causing dermal heating. The immediate effect is heat-induced collagen contraction, which may cause mild and possibly short-term skin tightening and wrinkle reduction. More importantly, the longer-term effect is skin remodeling, –similarly to a number of other directed energy treatments, it triggers new collagen formation, leading to a longer-term improvement in wrinkles and some skin tightening, although individual responses vary significantly. Laser energy in the near- and mid-infrared locations on the spectrum is weakly attracted to melanin making it suitable for patients of all skin colors.
Nd:YAG lasers are one of the most common types of laser, and are used for many different applications. Nd:YAG (neodymium-doped yttrium aluminium garnet; Nd:YAG) is a crystal that is used as a lasing medium for solid-state lasers. The dopant, triply ionized neodymium, typically replaces yttrium in the crystal structure of the yttrium aluminium garnet (YAG), since they are of similar size. Generally the crystalline host is doped with around 1% neodymium by weight. Nd:YAG lasers are optically pumped using a flashlamp or laser diodes.
Nd:YAG lasers typically emit light with a wavelength of 1064 nm, in the infrared. However, there are also transitions near 940, 1120, 1320, and 1440 nm. Nd:YAG lasers operate in both pulsed and continuous mode. Pulsed Nd:YAG lasers are typically operated in the so called Q-switching mode: In this Q-switched mode output powers of 20 megawatts and pulse durations of less than 10 nanoseconds are achieved. The high-intensity pulses may be efficiently frequency doubled to generate laser light at 532 nm, or higher harmonics at 355 and 266 nm.
The amount of the neodymium dopant in the material varies according to its use. For continuous wave output, the doping is significantly lower than for pulsed lasers. The lightly doped CW rods can be optically distinguished by being less colored, almost white, while higher-doped rods are pink-purplish.
There are a variety of such systems on the market, including but not limited to the following: CoolTouch (Nd:YAG laser 1320 nm), SmoothBeam (diode laser 1450 nm), Erbium Glass laser (1540 nm), Titan (1100 – 1800 nm). An increasing body of evidence suggests that lasers in the mid-infrared range may be the best choice for safe nonablative anti-aging therapy on a wide range of skin types: the 1320-nm neodyminium:yttrium-aluminum-garnet (Nd:YAG) laser (CoolTouch) and the Long-pulsed 1064-nm Nd:YAG laser (Lyra, Laserscope, San Jose, California). Both the 1320-nm Nd:YAG laser and the 1064-nm Nd:YAG laser are coupled with a skin-cooling device.
Nonablative Laser Home System
Laser treatments have become a popular means of treating both wrinkles and acne, particularly in the European and US markets. The latest development in that particular market is the rise of hand-held technologies that can be administered in the home. Companies marketing these kind of technologies include a partnership between Cynosure and Unilever and Palomar Medical Technologies. Several companies already see the potential of developing professional electrical treatments for home use. Both Procter and Gamble and L’Oreal taken on the market releasing light and laser based treatments for both hair removal and wrinkle reduction. Furthermore, the market development gets a mention in the upcoming HBA trade show’s conference program, when home-based laser and light systems, and the potential for formulating complimentary skin care products will be discussed.
Nulase – New Laser Technology for Anti-Aging Skin Rejuvenation at Home
NuLase Soft Touch Laser has been designed to penetrates the top layers of the skin, sending a message to our skin cells to produce more cellular energy, commonly called ATP. ATP (or: adenosine triphosphate) is the fuel our skin cells use for repair and rejuvenation. Increased ATP allows a faster acceptance of nutrients in cells. Research has shown that laser therapy can increase cellular ATP by as much as 150%, contributing to a better looking skin. The Soft Touch Laser’s light penetrates the skin, stimulating cellular energy, rejuvenation and repair, for a youthful, smooth, and silky appearance. The Soft Touch Laser by Nulase emits a safe and gentle laser light that oscillates in a uniform parallel wavelength targeting and gently stimulating your skin cells to obtain an enriching and dynamic effect on the look of your skin. On average, most people will see a significant difference in the look of their skin within one or two weeks, in some cases after the first application and treatment:
The Soft Touch Laser does not cut, harm, burn or inflame the skin. The Soft Touch Laser leaves the skin refreshed with a rejuvenated feeling, therefore no pain is involved. In over 30 years of international research and studies, no side effects from this type of applied low level laser therapy was found.
Nulase Soft Touch Laser comes along with a topical skin care system that enhanced it. A patented Nano Delivery System is used to feed your skin cells with “specific nutrients” that react with light energy. If you feed your cells the right restorative nutrients and add low level laser, the result will be a beautiful new complexion.
- Nonablative Laser Systems – Classification
- Nonablative Infrared Laser System
- Nonablative Fractional Laser Therapy
- Anti-Aging Nonablative Laser Home System Reviews