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Clinical improvement of photoaging-associated facial hyperpigmentation in Korean skin with a picosecond 1064-nm neodymium-doped yttrium aluminum garnet laser
摘要： Traditional attempts at alleviating photoaging-associated facial pigmentation conditions such as melasma, mottled hyperpigmentation, and post-inflammatory hyperpigmentation have yielded disfiguring cosmetic results. Laser toning using a low-fluence Q-switched 1064-nm neodymium-doped yttrium aluminum garnet (Nd:YAG) laser has been more commonly applied to date. However, the treatment efficacy and safety of this approach have not been widely reported. This study therefore evaluated the efficacy and safety of picosecond 1064-nm Nd:YAG laser application for photoaging-associated facial pigmentation treatment in Korean subjects. Forty-seven Korean subjects with photoaging-associated facial pigmentation underwent picosecond 1064-nm laser application. The clinical improvement of 17 patients was assessed by objective measurements such as melanin and erythema indices. All subjects received six biweekly treatments with the laser in a three-pass fashion delivering approximately 2000 to 2500 shots using a zoom handpiece with a spot size of 7 mm, fluence ranging from 0.4 to 0.7 J/cm2, and a repetition rate of 10 Hz. Clinicians evaluated the improvement of pigmentation using the pigmentation area and severity index (PSI), and subjects reported their satisfaction level on a four-point scale. Statistical analyses were performed using the SPSS version 19.0 for Windows software program (IBM Corp., Armonk, NY, USA). Forty-seven subjects (45 females and two males) completed this study with a 12-week follow-up period. The average decrease in PSI value at 12 weeks after treatment was 6.85 ± 6.35 points (p < 0.001). The average decreases in the values of the erythema and melanin indices were 19.41 ± 64.64 points (p = 0.234) and 28.88 ± 32.89 points (p = 0.002). An analysis of 32 subjects’ reports (68.1%) suggested good or excellent improvement. No serious adverse effects were observed during treatment or the follow-up period. Picosecond 1064-nm Nd:YAG laser application appears to be safe and effective in improving various photoaging-associated facial pigmentation conditions in Korean skin.
关键词： Melasma,pigmentation,Aging,Picosecond laser,Skin
更新于2025-09-23 15:19:57
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Development of Picosecond Laser Writing for Heat Resistant FBG Sensors and Adhesion Technique for High Temperature Industrial Plants; ?????3?§??????????????·￥?????????è????±FBG ?????3??μè￡??????¨é???????￡?￥-??¨????????3???????????￥???;
摘要： Pulse laser processing point by point method is applied for heat resistant Fiber Bragg Grating structure. In order to fabricate fine FBG, a close packaged picosecond laser system is used with a CCD camera microscopy. An optical fiber is mounted on a precision translation stage. The stage speed is controlled by the current position and the corrector output. In order to contact the FBG on a metal surface, nano-size colloidal silver adhesive is used under temperature monitoring. Heat expansion of SUS plate can be successfully monitored by strain gauge of the heat resistant FBG. It can be available for monitoring the structural integrity of high temperature industrial plant. Complex coolant piping systems of liquid sodium and molten salt are facing the risk of coolant leakage, which is the most promising usage.
关键词： Structural Health Integrity,Picosecond Laser Processing,Adhesion,High Temperature,FBG
更新于2025-09-23 15:19:57
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Comparison of fractional neodymium-doped yttrium aluminum garnet (Nd:YAG) 1064-nm picosecond laser and fractional 1550-nm erbium fiber laser in facial acne scar treatment
摘要： To compare the safety and efficacy of fractional neodymium-doped yttrium aluminum garnet (Nd:YAG) 1064-nm picosecond laser and fractional 1550-nm erbium fiber laser in acne scar treatment and to assess the adverse effects and complications of the two devices. Thirty patients with cosmetically similar acne scars on both sides of the faces were enrolled and treated four times at 4-week intervals. Each side of the face was treated with either fractional 1064-nm Nd:YAG picosecond laser or fractional 1550-nm erbium fiber laser. Efficacy was evaluated using digital photography taken at baseline and 5 months by a blinded dermatologist using the ECCA grading scale (échelle d’évaluation clinique des cicatrices d’acné). Patient overall satisfaction and self-rated improvement scores were recorded at baseline and 5 months. Adverse effects were recorded at every visit. Twenty-seven patients completed the study. Both devices demonstrated significant median ECCA score improvement from baseline (P < 0.001). However, there was no significant difference between the two in terms of median ECCA score improvement, patients’ perception of scar improvement, and overall satisfaction. Considering the adverse effects, more pinpoint bleeding was significantly observed with the picosecond laser (P = 0.002), whereas more pain was noted with the erbium laser (P < 0.001). Both fractional 1064-nm Nd:YAG picosecond laser and fractional 1550-nm erbium fiber laser are safe and effective in the treatment of acne scars. Costs should be taken into consideration when deciding on which device to use to maximize treatment outcomes.
关键词： Erbium fiber laser,Acne scar,Picosecond laser,Acne scar treatment,Fractional laser
更新于2025-09-19 17:13:59
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A Randomized, Splita??Face, Doublea??Blind Comparison Trial Between Fractionated Frequencya??Doubled 1064/532a??nm Picosecond Nd:YAG Laser and Fractionated 1927a??nm Thulium Fiber Laser for Facial Photorejuvenation
摘要： Fractionated lasers are a popular therapeutic option for facial photorejuvenation. In this study, we compare the safety, tolerability, and efficacy of a fractionated frequency‐doubled 1064/532 nm picosecond Nd:YAG fractionated picosecond laser (FPL) versus a fractionated 1927 nm thulium fiber laser (TFL) for facial rejuvenation. This was a double‐blind, randomized, split‐face comparison study involving 20 subjects. Facial halves were randomized to receive either FPL or TFL treatment. Three treatments were delivered at 1‐month intervals. Subjects were followed up for 1, 3, and 6 months post‐final treatment session and evaluated by blinded, non‐treating investigators for dyspigmentation, erythema, keratosis, texture, and rhytids on a standardized scale. Subjects also recorded a quantitative daily diary rating healing progress for 14 days after every treatment session. Statistically significant improvements in elastosis, erythema, keratosis, dyschromia, and skin texture were noted in both treatment groups. There were no significant differences detected in clinical efficacy between the two groups. Subject daily diaries revealed statistically significant differences in tolerability during the immediate 14‐day post‐operative recovery period. The facial half treated with FPL displayed significantly less redness on days 3 and 4; significantly less swelling on day 5; significantly less crusting on days 1 through 9; significantly less peeling on days 3 through 9; and significantly less itch on days 4 and 7. There were no unexpected adverse effects observed. Both FPL and TFL are safe and effective treatment options for facial rejuvenation. FPL may be associated with significantly less downtime.
关键词： photodamage,laser induced optical breakdown,photothermolysis,thulium fiber,picosecond laser,photoacoustolysis,Nd:YAG,holographic lens,clinical trial,rejuvenation
更新于2025-09-19 17:13:59
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Roughness and wettability properties of plain and silica-coated copper surfaces textured with picosecond laser
摘要： Many recent studies have investigated the mechanism of wettability transition of laser-textured copper surfaces on di?erent materials. Furthermore, several such studies have focused on approaches to accelerate wettability transition from hydrophilicity to hydrophobicity, such as temperature annealing and the use of chemical solutions. However, few researchers have focused on maintaining the initial hydrophilicity of laser-textured surfaces. This study presents a hybrid surface modi?cation method involving chemical bath deposition and ultrafast laser. First, the selected copper substrates are modi?ed using the sol-gel method through dip coating. Subsequently, the coated copper surfaces are irradiated with a picosecond laser. After laser texturing, bumpy structures are formed, and SiO2 nanoparticles can be sintered on the surfaces. Thus, the original hydrophilicity can be maintained, and the surface roughness can be enhanced simultaneously. By using this hybrid modi?cation method, a heterogeneous surface with high-precision patterns can be obtained. Moreover, the mechanism of wettability transition of laser-textured copper surfaces with di?erent laser ?uences is discussed using the Wenzel and Cassie Baxter wetting model by analyzing the chemical composition and surface morphology of the treated surfaces.
关键词： Roughness,Copper,Laser texturing,Wettability,Picosecond laser,Sol-gel
更新于2025-09-19 17:13:59
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Retrospective photographic review of nontattoo indications treated by picosecond laser
摘要： Background: Picosecond (PS) lasers were approved by the US FDA in 2012 after being shown to remove tattoos with more success and fewer treatments compared with traditional methods. PS lasers were shown to be versatile, indicated for the treatment of lentigines, café-au-lait macules (CALMs), and acne scars and skin rejuvenation. Objective: We report our experience treating our patients for different indications using a PS laser. Methods: We performed a retrospective chart and photographic review of all patients seen between 2016 and 2018 that were treated in our centers with a PS laser for nontattoo indications. Clinical outcomes were evaluated using side-by-side comparisons of the clinical photographs by two blinded, independent physicians using a visual analog scale consisting of six levels of treatment response. Results: A total of 233 patients were studied. Most sought treatment for solar lentigo (27%) and skin rejuvenation (14%). Epidermal nevi exhibited the greatest improvement with treatment, while acne scarring demonstrated the least. Only 24% of patients experienced noteworthy, transient adverse effects. Conclusion: Picosecond lasers were efficacious and safe for a variety of indications. They were effective in treating epidermal nevi and pigmented lesions, such as Lentigines and CALMs.
关键词： aesthetic improvement,epidermal nevus,picosecond laser,laser treatment,solar lentigines
更新于2025-09-19 17:13:59
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Modification characteristics of filamentary traces induced by loosely focused picosecond laser in sapphire
摘要： The ability of loosely focused picosecond laser to induce filamentation (4.8 times the Rayleigh length) in sapphire was confirmed. The morphology and microstructure of the filamentary traces under typical pulse energy were studied, in which the colorful birefringence phenomenon and damage defects were detected in sapphire. Irreversible ceramic-like polycrystalline microstructures were formed in filamentary traces, and the phase transition from α-Al2O3 to γ-Al2O3 directly reflected the thermal effect of picosecond laser filamentation. According to the filamentary characteristics, a continuous filamentary channel with a uniform diameter of 33 μm and a length of 7443 μm was obtained by gradually raising the focal position. The research provides first-hand information for the high throughput micro-cutting, micro drilling and thin slicing of sapphire based on ultrafast laser non-linear effects.
关键词： Phase transition,Modification,Picosecond laser,Filamentation,Sapphire
更新于2025-09-19 17:13:59
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An experimental investigation of laser drilling nitrile butadine (NBR) rubber
摘要： This paper focusses on understanding laser-NBR rubber interactions in particular the effect of laser wavelength and pulse width on material removal and thermal damage. Three lasers with wavelengths at 355 nm, 795 nm and 1064 nm and pulse duration at 30 ns, 10 ps and 130 fs, respectively, have been investigated for their optical absorption, heat conduction and their material removal mechanisms in high aspect ratio drilling of NBR rubber. It is interesting to find that under certain conditions, the ultrashort pulse lasers (both the femtosecond and picosecond lasers) did not lead to better results than the nanosecond UV laser in drilling hole profile (straightness and thermal damage), aspect ratio and amount of the ablated material re-deposition on the substrate surfaces. The results implied that there is heat conduction and thermal damage even with ultrashort laser pulses when the processing conditions are not appropriate. Firing laser pulses intermittently was shown to reduce thermal accumulation. Experimental studies showed that the 355-nm Nd:YAG laser (UV laser) achieved higher material removal rate with high aspect ratio as compared to the ultrashort laser pulses in drilling the NBR substrates.
关键词： NBR rubber,Pulse width effect,Picosecond laser drilling,UV laser drilling,Femtosecond laser drilling
更新于2025-09-16 10:30:52
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Good-Quality and High-Efficiency Dicing for Thick LiNbO3 Wafers Using Picosecond Laser Pulses
摘要： Lithium niobate (LiNbO3) has become popular with applications in electronics and communication industries due to its excellent electro-optical and nonlinear properties. This paper presents the influence of laser power, repetition frequency, number of subpulses, depth of each pass, and scanning velocity in picosecond laser dicing on multiple characteristics of LiNbO3 using the Taguchi method. By means of analysis of variance and analysis of relations between the characteristics, the optimal ps-laser-dicing parameter is obtained with good quality and high efficiency, which is applied to LiNbO3 products. The result indicates that picosecond laser dicing provides an alternative to machine thick LiNbO3 wafers with narrow kerf width, micro chipping, smooth surface, and high productivity.
关键词： thick lithium niobate,picosecond laser,LiNbO3 wafers,laser dicing,dicing quality optimization
更新于2025-09-16 10:30:52
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[Laser Institute of America ICALEO?? 2014: 33rd International Congress on Laser Materials Processing, Laser Microprocessing and Nanomanufacturing - San Diego, California, USA (October 19a??23, 2014)] International Congress on Applications of Lasers & Electro-Optics - Towards the production of glass based printed circuit boards
摘要： This study analyzes laser processing of glass-based printed circuit boards which have the capability to replace conventional substrate materials when electronics are required to operate at elevated temperatures. There is significant potential for glass-based circuit boards within the field of aerospace and electric mobility. The new circuit board concept consists of thin copper-coated borosilicate glass with thicknesses ranging from 150 μm to 500 μm. Conventional mechanical processing of this new circuit boards induces stress on the thin glass which can lead to damage of the substrate. Therefore, laser processing with a picosecond laser source is suggested as a tool within the production process of the new circuit boards. Two necessary processes are investigated using a pulsed picosecond laser with a pulse duration of 7 ps at a wavelength of 515 nm. Precise drill-holes for vertical connections of multilayer boards were produced where chipping at the cutting edge must be avoided. Selective ablation of the copper coating was performed to generate the electrical circuits. The results show that a well-defined ablation process is crucial to achieve adequate electrical isolation without damaging the glass substrate. The study also underlines the huge potential of laser processing with picosecond laser sources, which have proven to be a versatile instrument to drill thin glass and generate electrical circuits by selective ablation.
关键词： copper ablation,picosecond laser,laser processing,borosilicate glass,glass-based printed circuit boards
更新于2025-09-16 10:30:52