Treatment of resistant tattoos using a new generation Q-switched Nd:YAG laser: Influence of beam profile and spot size on clearance success

High power Ho:Y2O3 ceramic laser with controllable output intensity profile at 2.1 µm

We report on a high-power Ho:Y₂O₃ ceramic laser at 2.1 µm with controllable output beam profile ranging from LG₀₁ donut, flat-top to TEM₀₀ mode using a simple two-mirror resonator. In-band pumped at 1943nm using a Tm fiber laser beam shaped via a coupling optics comprising a capillary fiber and lens-combination to achieve distributed pump absorption in Ho:Y₂O₃ and hence selective excitation of the target mode, the laser yields 29.7 W of LG₀₁ donut, 28.0 W of crater-like, 27.7 W of flat-top and 33.5 W of TEM₀₀ mode output for absorbed pump power of 53.5 W, 56.2 W, 57.3 W and 58.2 W, respectively, corresponding to a slope efficiency of 58.5%, 54.3%, 53.8% and 61.2%. This is, to the best of our knowledge, the first demonstration of laser generation with continuously tunable output intensity profile at ∼2 µm wavelength region.

Cavity-dumped burst-mode Nd:YAG laser master-oscillator power-amplifier system with a flat-top beam output realized by gain profile-controlled side pumping

We report a compact cavity-dumped burst-mode Nd:YAG laser master-oscillator power-amplifier system with a flat-top intensity distribution across the output-beam section. Custom-designed gain profile-controlled diode side pumping modules providing flat-top and concave gain profiles were utilized to generate a uniform beam profile and suppress thermal lensing during amplification, respectively. Bursts with an energy of 2.0 J and duration of 1.6 ms were operated at 10 Hz. Within the bursts, single pulses with an energy of 12.7 mJ and pulse width of 3.3 ns were achieved at 100 kHz.

Comparing the efficacy and safety of laser treatments in tattoo removal: A systematic review

BACKGROUND

Although lasers have been the criterion standard for tattoo removal, selecting the best modality can be challenging because of the varying efficacies and adverse effects.

OBJECTIVE

To evaluate all lasers used to remove tattoos and assess their efficacies and adverse effects.

METHODS

Our systematic review searched PubMed, MEDLINE, Embase, Scopus, CINAHL, Cochrane Central Register of Trials, and ClinicalTrials.gov for all laser treatments. The outcomes measured included laser parameters, treatment methods, patient and tattoo characteristics, clearance rate, and adverse effect rate. The quality of the included articles was appraised by using specific assessment tools and given a high, moderate, or low risk of bias.

RESULTS

Our search led to 3037 studies, with 36 being included in the systematic review (7 randomized controlled trials, 2 nonrandomized controlled trials, and 27 case series). Although quality-switched neodymium-doped yttrium-aluminum-garnet lasers are safe and effective, picosecond lasers have shown superiority with blue, green, and yellow tattoo pigments. Both are safe and effective for black tattoos.

LIMITATIONS

Variability among studies.

CONCLUSIONS

Picosecond lasers show superiority when treating blue, green, and yellow tattoos. The R20 and R0 novel techniques can effectively reduce treatment time. Further randomized controlled trials are required to make a more definitive recommendation.

Laser tattoo removal: a clinical update

Techniques for tattoo removal have evolved significantly over the years. The commonly used Quality-switched (QS) ruby, alexandrite, and Nd:YAG lasers are the traditional workhorses for tattoo removal. Newer strategies using combination laser treatments, multi-pass treatments, and picosecond lasers offer promising results. The tattoo color and skin type of the patient are important considerations when choosing the appropriate laser. Standard protocols can be developed for the effective and safe treatment of tattoos.

Controlling the optical fiber output beam profile by focused ion beam machining of a phase hologram on fiber tip

A phase hologram was machined on an optical fiber tip using a focused ion beam (FIB) system so that a ring-shaped beam emerges from the fiber tip. The fiber used for this work was a commercial single-mode optical fiber patch cable for a design wavelength of 633 nm with a germanosilicate core. The ring-shaped beam was chosen to ensure a simple geometry in the required phase hologram, though the Gerchberg-Saxton algorithm can be used to calculate a hologram for an arbitrary beam shape. The FIB machining took approximately 45 min at 30 kV and 200 pA. The radius of the resulting ring beam was 0.083 m at 1 m standoff, as compared to 0.1 m as was initially desired. Results suggest that this imaging technique may provide a basis for a beam-shaping method with several advantages over the current commercial solutions, having permanent alignment, compactness, and mechanical robustness. However, it would appear that minimizing the speckle pattern will remain a critical challenge for this technique to become widely implemented.

A webcam in Bayer-mode as a light beam profiler for the near infra-red

Beam profiles are commonly measured with complementary metal oxide semiconductors (CMOS) or charge coupled devices (CCD). The devices are fast and reliable but expensive. By making use of the fact that the Bayer-filter in commercial webcams is transparent in the near infra-red (>800 nm) and their CCD chips are sensitive up to about 1100 nm, we demonstrate a cheap and simple way to measure laser beam profiles with a resolution down to around ±1 μm, which is close to the resolution of the knife-edge technique.

Latest innovations for tattoo and permanent makeup removal

The goal of this article is to reveal the latest techniques and advances in laser removal of both amateur and professional tattoos, as well as cosmetic tattoos and permanent makeup. Each pose different challenges to the removing physician, but the goal is always the same: removal without sequelae. The authors' technique is detailed, and discussion of basic principles of light reflection, ink properties, effects of laser energy and heat, and outcomes and complications of tattoo removal are presented.