Laser tattoo removal was performed with continuous-wave lasers initially, and later with Q-switched lasers, which became commercially available in the early 1990s. Today, “laser tattoo removal” usually refers to the non-invasive removal of tattoo pigments using Q-switched lasers. Typically, black and other darker-colored inks can be removed completely.
Continuous wave lasers are those lasers that emit a beam whose output power is constant over time. Such a laser is known as continuous wave (CW). Many types of lasers can be made to operate in continuous wave mode to satisfy such an application. Many of these lasers actually lase in several longitudinal modes at the same time, and beats between the slightly different optical frequencies of those oscillations will in fact produce amplitude variations on time scales shorter than the round-trip time (the reciprocal of the frequency spacing between modes), typically a few nanoseconds or less. In most cases these lasers are still termed “continuous wave” as their output power is steady when averaged over any longer time periods, with the very high frequency power variations having little or no impact in the intended application. This was the first type of laser used in laser tattoo removal.
Q-switch Lasers are those lasers that produce a pulsed output beam. The technique allows the production of light pulses with extremely high energy, 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 type of pulse generation with lasers, Q-switching leads to much lower pulse repetition rates, much higher pulse energies, and much longer pulse duration. The two techniques are sometimes applied together. This is the most common, current technique used for laser tattoo removal.
Lasers remove tattoos by breaking up the pigment colors with a high-intensity light beam. Black tattoo pigment absorbs all laser wavelengths, making it the easiest color to treat. Other colors can only be treated by selected lasers based upon the pigment color. Certain tattoo pigments, such as yellows, greens and fluorescent inks are more challenging to treat than darker blacks and blues. The reason why these pigments are more challenging is because they have absorption spectra that fall outside or on the edge of the emission spectra available in the laser tattoo removal device being used. Recent pastel colored inks contain high concentrations of titanium dioxide which is highly reflective. Consequently, such inks are difficult to remove using current laser tattoo removal techniques since they reflect a significant amount of the incident light energy out of the skin.
Smaller tattoos will require fewer pulses while larger ones will need more to remove them. In either case, to completely get rid of a tattoo, it will take several treatments. After each visit, your tattoo should become progressively lighter.
Laser tattoo removal is uncomfortable, but most patients don’t need a general anesthesia. Depending on the location of your tattoo, you may want to apply a topical anesthesia cream beforehand or have it applied by the attending physician or laser tattoo removal technician.
Immediately following the treatment, use an ice pack to soothe the treated area. And apply an antibiotic cream or ointment and bandage to protect it. You should also be sure it’s covered with sunblock when you’re outside.