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Actas Dermo-sifiliograficas 2022Burn scars cause high morbidity in the form of contractures, body disfigurement, and itching, and they also have a high emotional impact that adversely affects patient... (Review)
Review
Burn scars cause high morbidity in the form of contractures, body disfigurement, and itching, and they also have a high emotional impact that adversely affects patient quality of life. Laser therapy has proven effective in this setting. It is superior to topical treatments and can be used in conjunction with surgery, helping to reduce morbidity. The use of lasers in hospital dermatology departments, however, is still limited. Carbon dioxide laser resurfacing is the most widely used modality for reducing scar thickness, improving textural abnormalities, and treating contractures. Treatments improve mobility for patients with constrictions. Pulsed dye laser treatments are particularly useful for reducing erythema in recent burn scars and preventing subsequent hypertrophy. Pigment laser treatments with short pulse durations (nanoseconds or picoseconds) can improve hyperpigmentation. In this article, we review the evidence for the use of laser therapy for burn scars and propose a treatment algorithm.
Topics: Humans; Cicatrix; Cicatrix, Hypertrophic; Lasers, Gas; Burns; Quality of Life; Laser Therapy; Contracture; Treatment Outcome
PubMed: 35963335
DOI: 10.1016/j.ad.2022.06.018 -
Lasers in Medical Science Jan 2023Picosecond lasers have a very short pulse duration and a high peak power density. When fractional optical delivery systems are attached to picosecond lasers, they... (Review)
Review
Picosecond lasers have a very short pulse duration and a high peak power density. When fractional optical delivery systems are attached to picosecond lasers, they generate an array of concentrated microspots with a high fluence surrounded by areas with a low fluence. This article discusses the histologic characteristics and clinical applications of fractional picosecond laser treatment. Fractional picosecond laser produces laser-induced optical breakdown (LIOB) and laser-induced cavitation (LIC) in the epidermis and dermis respectively, and can encourage skin regeneration and dermal remodeling. It has been shown that fractional picosecond laser has a positive effect on facial photoaging, enlarged facial pores, dyspigmentation, wrinkles, and atrophic scars. Further research is still needed to confirm the benefits of fractional picosecond lasers.
Topics: Humans; Lasers, Solid-State; Skin; Epidermis; Cicatrix; Pigmentation Disorders; Treatment Outcome
PubMed: 36658259
DOI: 10.1007/s10103-022-03704-y -
Frontiers in Physics 2023Brillouin microscopy based on spontaneous Brillouin scattering has emerged as a unique elastography technique because of its merit of non-contact, label-free, and...
Brillouin microscopy based on spontaneous Brillouin scattering has emerged as a unique elastography technique because of its merit of non-contact, label-free, and high-resolution mechanical imaging of biological cell and tissue. Recently, several new optical modalities based on stimulated Brillouin scattering have been developed for biomechanical research. As the scattering efficiency of the stimulated process is much higher than its counterpart in the spontaneous process, stimulated Brillouin-based methods have the potential to significantly improve the speed and spectral resolution of existing Brillouin microscopy. Here, we review the ongoing technological advancements of three methods, including continuous wave stimulated Brillouin microscopy, impulsive stimulated Brillouin microscopy, and laser-induced picosecond ultrasonics. We describe the physical principle, the representative instrumentation, and biological application of each method. We further discuss the current limitations as well as the challenges for translating these methods into a visible biomedical instrument for biophysics and mechanobiology.
PubMed: 37377499
DOI: 10.3389/fphy.2023.1175653 -
Dermatologie (Heidelberg, Germany) Jun 2023The picosecond laser is one of the latest laser systems in dermatology and was originally developed to optimize tattoo removal. Advances in this technology has expanded... (Review)
Review
BACKGROUND
The picosecond laser is one of the latest laser systems in dermatology and was originally developed to optimize tattoo removal. Advances in this technology has expanded the use of the picosecond laser to numerous other indications.
OBJECTIVES
This article provides an overview of the technical background as well as the indications of the picosecond laser in dermatological laser medicine and elucidates the possibilities and limits of this laser system.
MATERIALS AND METHODS
The article is based on a review of the current literature as well as experience from clinical practice in a university laser department.
RESULTS
The picosecond laser enables a particularly gentle and effective treatment due to ultra-short pulses and the principle of laser-induced optical breakdown. Compared to Q‑switched lasers, the picosecond laser has fewer side effects and is associated with lower pain intensity and shorter downtime. In addition to the removal of tattoos and pigmentary disorders, it is also used in the treatment of scars and rejuvenation.
CONCLUSIONS
The picosecond laser has a wide range of indications in dermatological laser medicine. The current data indicate that the laser is an effective method with few side effects. Further prospective studies have to be conducted to assess the efficacy, tolerability and patient satisfaction in an evidence-based manner.
Topics: Humans; Prospective Studies; Dermatology; Lasers; Tattooing; Laser Therapy; Drug-Related Side Effects and Adverse Reactions
PubMed: 37099130
DOI: 10.1007/s00105-023-05144-3 -
Sensors (Basel, Switzerland) Apr 2021Fast gating in Raman spectroscopy is used to reject the fluorescence contribution from the sample and/or the substrate. Several techniques have been set up in the last... (Review)
Review
Fast gating in Raman spectroscopy is used to reject the fluorescence contribution from the sample and/or the substrate. Several techniques have been set up in the last few decades aiming either to enhance the Raman signal (CARS, SERS or Resonant Raman scattering) or to cancel out the fluorescence contribution (SERDS), and a number of reviews have already been published on these sub-topics. However, for many reasons it is sometimes necessary to reject fluorescence in traditional Raman spectroscopy, and in the last few decades a variety of papers dealt with this issue, which is still challenging due to the time scales at stake (down to picoseconds). Fast gating (<1 ns) in the time domain allows one to cut off part of the fluorescence signal and retrieve the best Raman signal, depending on the fluorescence lifetime of the sample and laser pulse duration. In particular, three different techniques have been developed to accomplish this task: optical Kerr cells, intensified Charge Coupling Devices and systems based on Single Photon Avalanche Photodiodes. The utility of time domain fast gating will be discussed, and In this work, the utility of time domain fast gating is discussed, as well as the performances of the mentioned techniques as reported in literature.
PubMed: 33916972
DOI: 10.3390/s21082579 -
Photoacoustics Jun 2023This review discusses picosecond ultrasonics experiments using ultrashort hard x-ray probe pulses to extract the transient strain response of laser-excited nanoscopic... (Review)
Review
This review discusses picosecond ultrasonics experiments using ultrashort hard x-ray probe pulses to extract the transient strain response of laser-excited nanoscopic structures from Bragg-peak shifts. This method provides direct, layer-specific, and quantitative information on the picosecond strain response for structures down to few-nm thickness. We model the transient strain using the elastic wave equation and express the driving stress using Grüneisen parameters stating that the laser-induced stress is proportional to energy density changes in the microscopic subsystems of the solid, i.e., electrons, phonons and spins. The laser-driven strain response can thus serve as an ultrafast proxy for local energy-density and temperature changes, but we emphasize the importance of the nanoscale morphology for an accurate interpretation due to the Poisson effect. The presented experimental use cases encompass ultrathin and opaque metal-heterostructures, continuous and granular nanolayers as well as negative thermal expansion materials, that each pose a challenge to established all-optical techniques.
PubMed: 37275326
DOI: 10.1016/j.pacs.2023.100503 -
Materials (Basel, Switzerland) Sep 2023In this work, we present the fabrication of thin films/nanostructures of metals and metal oxides using picosecond laser ablation. Two sets of experiments were performed:...
In this work, we present the fabrication of thin films/nanostructures of metals and metal oxides using picosecond laser ablation. Two sets of experiments were performed: the depositions were carried out in vacuum and in air at atmospheric pressure. The subjects of investigation were the noble metals Au and Pt and the metal oxides ZnO and TiO. We studied and compared the phase composition, microstructure, morphology, and physicochemical state of the as-deposited samples' surfaces in vacuum and in air. It was found that picosecond laser ablation performed in vacuum led to the fabrication of thin films with embedded and differently sized nanoparticles. The implementation of the same process in air at atmospheric pressure resulted in the fabrication of porous nanostructures composed of nanoparticles. The ablation of pure Pt metal in air led to the production of nanoparticles with an oxide shell. In addition, more defects were formed on the metal oxide surface when the samples were deposited in vacuum. Furthermore, the laser ablation process of pure Au metal in a picosecond regime in vacuum and in air was theoretically investigated using molecular dynamics simulation.
PubMed: 37834498
DOI: 10.3390/ma16196364 -
Laser Therapy Jul 2020Rejuvenation therapy using picosecond pulse laser and picosecond pulsed fractional therapy with a fractional lens have been performed with clinical effects evaluated....
BACKGROUND AND AIMS
Rejuvenation therapy using picosecond pulse laser and picosecond pulsed fractional therapy with a fractional lens have been performed with clinical effects evaluated. However, no histological analysis of effects on photoaged skin exists. In this study, influence of laser-toning and fractional therapy using picosecond pulse laser on photoaging was histologically investigated.
SUBJECTS AND METHODS
The flexor side forearm of a male, age 61, with photoaging was divided into three 20 cm areas and irradiated with approximately 400 shots of 10-Hz laser, 8 mm spot size, and nine passes at an output of 0.7, 0.9, and 1.1 J/cm using picosecond laser-toning therapy six times, every two weeks. Two weeks post final irradiation, 2 mm punch biopsies were taken from the irradiation fields. Fractional therapy using Micro Lens Array (MLA) attached picosecond fractional therapy was applied to the medial crural skin with marked photoaging of a male, age 63. Irradiation was applied at 0.5 and 0.7 J/cm through two passes, with 3 mm punch biopsies taken from each irradiation field immediately after and again two months post-irradiation. Samples were subjected to hematoxylin and eosin (HE) and Elastica van Gieson staining and compared.
RESULTS
In the picosecond laser-toning therapy sample, photoaging-induced dermis reconstruction occurred. The picosecond fractional therapy sample showed both epidermis and dermis reconstruction, with intrinsic aging and photoaging improvements.
CONCLUSIONS
Recovery of dermal and epidermal age related atrophy by picosecond laser-toning and picosecond fractional therapy was histologically confirmed. Picosecond fractional therapy demonstrated superior improvement.
PubMed: 32904059
DOI: 10.5978/islsm.20-OR-05 -
Medical Devices (Auckland, N.Z.) 2016The use of picosecond lasers to remove tattoos has greatly improved due to the long-standing outcomes of nanosecond lasers, both clinically and histologically. The first... (Review)
Review
BACKGROUND AND OBJECTIVES
The use of picosecond lasers to remove tattoos has greatly improved due to the long-standing outcomes of nanosecond lasers, both clinically and histologically. The first aesthetic picosecond laser available for this use was the PicoSure(®) laser system (755/532 nm). Now that a vast amount of research on its use has been conducted, we performed a comprehensive review of the literature to validate the continued application of the PicoSure(®) laser system for tattoo removal.
STUDY DESIGN AND METHODS
A PubMed search was conducted using the term "picosecond" combined with "laser", "dermatology", and "laser tattoo removal".
RESULTS
A total of 13 articles were identified, and ten of these met the inclusion criteria for this review. The majority of studies showed that picosecond lasers are an effective and safe treatment mode for the removal of tattoo pigments. Several studies also indicated potential novel applications of picosecond lasers in the removal of various tattoo pigments (eg, black, red, and yellow). Adverse effects were generally mild, such as transient hypopigmentation or blister formation, and were rarely more serious, such as scarring and/or textural change.
CONCLUSION
Advancements in laser technologies and their application in cutaneous medicine have revolutionized the field of laser surgery. Computational modeling provides evidence that the optimal pulse durations for tattoo ink removal are in the picosecond domain. It is recommended that the PicoSure(®) laser system continue to be used for safe and effective tattoo removal, including for red and yellow pigments.
PubMed: 27194919
DOI: 10.2147/MDER.S77993 -
Optics Express Jul 2023We report a high-energy, picosecond, mid-infrared (MIR) optical parametric oscillator (OPO), in which a length of hollow-core-fiber (HCF) is employed to enable operation...
We report a high-energy, picosecond, mid-infrared (MIR) optical parametric oscillator (OPO), in which a length of hollow-core-fiber (HCF) is employed to enable operation at 1-MHz repetition rate in a compact cavity format. The OPO is synchronously pumped by an ytterbium-doped-fiber (YDF) master-oscillator-power-amplifier (MOPA) system, seeded by a 1040-nm gain-switched laser diode (GSLD). Using periodically poled lithium niobate (PPLN) as the nonlinear crystal, the OPO generates signal and idler beams with tunable wavelengths in the range of 1329-1641 nm and 2841-4790 nm, respectively. The OPO provides 137-ps pulses with a maximum signal energy of 10.05 µJ at 1600 nm and a maximum idler energy of 5.13 µJ at 2967 nm. This, to the best of our knowledge, represents the highest energy MIR pulses, as well as the highest total converted pulse energy (15.18 µJ), ever achieved from a fiber laser pumped picosecond OPO.
PubMed: 37475426
DOI: 10.1364/OE.494037