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Laser for vascular anomalies: successful outcomes in children
摘要： Vascular anomalies can cause both emotional and physical distress to patients, particularly children. The paediatric laser service at Great Ormond Street Hospital (GOSH) treats a range of dermatological conditions including a variety of vascular anomalies, excess hair growth and disfiguring scars. The laser team at GOSH has 25 years of experience in treating a wide variety of paediatric dermatological conditions using various laser therapies. With over 600 new referrals for laser therapy and over 1000 laser procedures each year the GOSH laser team has vast amounts of experience with both common and rare conditions. Excellent clinical outcomes continue to be delivered, and new treatment therapies are constantly being developed to treat more recalcitrant lesions. The adverse effect rates experienced by the GOSH laser patients have been decreasing over the past two decades, reaching the low rate of 0.8% per treated patients per year. This remarkable achievement has been continuously improved by integrating specific and standardized laser protocols for each patient treated, to ensure efficacious and safe laser treatment delivery. Treating vascular anomalies with laser therapy creates significant positive results among the paediatric population, thus laser therapy at GOSH makes a significant impact upon children’s lives with both rare and common vascular anomalies.
关键词： Nd:YAG laser,paediatric dermatology,laser therapy,pulsed dye laser,vascular anomalies
更新于2025-09-11 14:15:04
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Experience of 138 Transurethral Urethrotomy With Holmium:YAG Laser
摘要： Introduction: Many valid option modalities are available for the management of urethral stricture disease (USD), such as internal urethrotomy which has the success rates of 33%–60%. The aim of this study was to assess the outcome of holmium: YAG (Ho: YAG) laser urethrotomy (HLU). Methods: One hundred thirty-eight patients with urethral stricture with the mean age of 48±3.03 years old treated by HLU from March 2011 to August 2017. The main purpose of this investigation was to evaluate mean operation time, stricture recurrence rate and post-operation Qmax and complications of transurethral HLU. Results: The most common cause of USD was trauma in 82 (59.4%) patients. Mean laser operation time, mean hospital stay and mean postoperative duration of catheterization were 23.08 ± 9.1 minutes, 19.02 ± 10.7 hours and 10.3 ± 1.05 days respectively. The mean Qmax was 8.3 ± 2.07 mL/s before surgery and 16 ±3.1 mL/s afterward. At the end of 12 months follow-up, a total of 37 (26.8%) patients developed recurrence of the stricture. Patients with posterior, longer urethral strictures and previous history of interventions have more recurrence rate of the stricture. Conclusion: HLU is minimally invasive and seems to be an effective and safe management option for primary, short, urethral strictures. The hospital stay is remarkably short and complications are negligible.
关键词： Holmium: YAG laser,Laser urethrotomy,Urethral stricture,Internal urethrotomy
更新于2025-09-11 14:15:04
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Posterior capsule opacification and Nd:YAG laser rates with two hydrophobic acrylic single-piece IOLs
摘要： Objectives To evaluate the development of posterior capsule opacification (PCO) and Nd:YAG capsulotomy rates following implantation of two hydrophobic acrylic IOLs. Methods In a randomized, controlled trial, 80 patients with bilateral senile cataract were implanted with the hydrophobic acrylic single-piece intraocular Lenses (IOLs) EyeCee One in one eye and iMics1 in the other. Outcomes of 39 patients (78 eyes) were evaluated after 3 years. Automated Quantification of After-Cataract (AQUA; for PCO occurrence), visual acuity, anterior fibrosis, capsule?optic edge interaction and distance between anterior and posterior capsule IOL surface were analysed. Results After a mean follow-up of 38 ± 1.95 months, Nd:YAG capsulotomy occurred at a rate of 15.4% and 46.2% in the EyeCee One and iMics1 groups, respectively (p < 0.01). Respective mean PCO scores measured by AQUA were 1.57 ± 1.63 and 2.45 ± 1.44 (p = 0.019). A distinct gap between the anterior capsule and the IOL optic was present in 89% of eyes implanted with EyeCee One and 13% of iMics1 eyes. A gap between the posterior capsule and the posterior surface of the lens was observed in 76% of EyeCee One eyes and 35% of iMics1 eyes. Conclusions Study findings suggest that PCO and Nd:YAG capsulotomy rates are significantly lower in eyes implanted with the EyeCee One IOL compared to the iMics1 IOL. Optic sharpness and lens material seem to be the decisive factors, while the stepped edge beneath the haptic junction appeared to be ineffective.
关键词： Nd:YAG laser,Posterior capsule opacification,EyeCee One,iMics1,hydrophobic acrylic IOLs
更新于2025-09-11 14:15:04
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[IEEE 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) - Berlin, Germany (2019.6.23-2019.6.27)] 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) - Application of MEMS Enabled Excitation and Detection Schemes to Photoacoustic Imaging
摘要： This paper shows, for the first time, a MEMS enabled photoacoustic system, using a custom MEMS Q-switched Nd:YAG laser for generation of photoacoustic (PA) waves and a custom-built MEMS thin-film aluminium nitride piezoelectric micromachined ultrasound transducers for PA wave detection.
关键词： Photoacoustic,Miniaturisation,PMUT,Aluminium Nitride,MEMS,Imaging,Q-switched Nd:YAG
更新于2025-09-11 14:15:04
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Mid-IR Laser Generating Ultrasound in a Polyetheretherketone Polymer
摘要： We demonstrate laser ultrasonic generation in polyetheretherketone (PEEK). A middle infrared ZnGeP2 optical parametric oscillator (ZGP-OPO) pumped by a Q-switched Ho:YAG laser is employed as the ultrasonic excitation source. The ZGP-OPO has a spectral range of 3.2–3.4 μm. At an output wavelength of 3.4 μm, the maximum average output power of ZGP-OPO is 3.05 W with a pulse width of 24.3 ns, corresponding to a peak power of approximately 127.5 kW. The ultrasound is generated by the laser converted from 3.2 to 3.4 μm in the PEEK composite. The maximum ultrasonic signal amplitude in PEEK is 33 mV under the condition of thermoelastic excitation at 3.4 μm. Ablation occurs in the CPRF sample when the energy fluence is over 122.45 mJ/cm2. PEEK has a stronger absorption at 3.4 μm and laser-ultrasound generation is influenced by the wavelength of the laser.
关键词： ZGP-OPO,Ho:YAG laser,polyetheretherketone,ultrasound,Mid-IR laser
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Efficient Tm:YAG and Tm:LuAG Lasers Pumped by Red Tapered Diodes
摘要： Eye-safe, diode-pumped all-solid-state lasers working in the 2 μm region are favourable for many applications including remote sensing, medicine, and gas sensing. Tm-doped crystals such as Tm:YAG and Tm:LuAG are among the commonly employed laser gain media for this purpose. These systems are usually pumped by laser diodes operating around 780 nm [1]. The corresponding stokes limit for laser slope efficiency is then about 39%. However, for highly-doped samples, the two-for-one cross-relaxation process enables laser efficiencies exceeding this limit, and a slope efficiency of 59% has been reported from a 785 nm Ti:Sapphire pumped Tm:YAG laser, indicating a cross-relaxation efficiency of around 1.5 (one 780 nm pump photon generating 1.5 laser photons around 2 μm) [2]. As an alternative pumping approach, Stoneman et al. pointed out the possibility to pump Tm-based lasers around 681 nm, due to the much stronger absorption line at this wavelength [3]. Compared to 785 nm pumping, using the stronger 681 nm line warrants utilization of shorter Tm-crystals, which minimizes self-absorption losses [3]. Moreover, 681 nm pumping could also facilitate usage of thinner crystals in thin-disk geometry and/or could decrease the required number of bounces on the thin-disk for sufficient absorption of the pump light [4]. Moreover, pumping at a wavelength with stronger absorption coefficient creates a more densely populated gain medium, which could increase the effectiveness of cross-relaxation process. As a drawback, the stokes limited slope efficiency reduces to around 34% for 681 nm pumping, and decreased absorption lengths might also induce stronger thermal effects. In their early work, Stoneman et al. used a Ti:Sapphire laser operating at 681 nm to pump a Tm:YAG crystal, but the obtained slope efficiency was only around 35%, indicating a weak cross-relaxation process [3]. In this work, we report highly efficient Tm:YAG and Tm:LuAG lasers pumped with high brightness tapered diodes operating around 681 nm [5]. The lasers crystals had a Tm-doping of 6%, a length of 7 mm, and absorbed around 98% of the incident TM polarized pump light. In the experiments, we have achieved slope efficiencies up to 52% and 51% in cw operation from Tm:YAG and Tm:LuAG lasers, respectively (Fig. 1). This efficiency indicates a cross-relaxation efficiency of around 1.55, which is similar to what was shown with the regular 785 nm diode pumping [2]. To the best of our knowledge, this is the first report of diode pumping of Tm-doped solid-state lasers at 681 nm, as well as the first usage of tapered diodes as pump sources in Tm-systems.
关键词： diode-pumped,681 nm,Tm:YAG,Tm:LuAG,lasers,tapered diodes
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - High-Power Dual-Comb Thin-Disk Oscillator
摘要： Dual-comb spectroscopy is a rapidly advancing spectrometric technique where the temporal interferograms generated with two asynchronous trains of pulses are recorded, and Fourier transformed to reveal the spectrum of an absorber in the beam path [1]. To date, best performance is achieved with systems involving complex active stabilization of two femtosecond erbium fiber lasers [1]. One way to simplify the technique is to generate a dual-comb output from a single laser cavity. However, there have been only a few demonstrations of such a scheme so far [2,3]. Here we present a dual-comb system based on a single thin-disk oscillator. The novel architecture effectively rejects common noise, with mutual coherence time exceeding one second without any active stabilization. Moreover, the system shows nearly an order of magnitude higher average and peak output powers compared to previous dual-comb demonstrations. Efficient nonlinear frequency conversion to the UV or mid-IR regions—of high interest to molecular spectroscopy—will thus be greatly facilitated.
关键词： thin-disk oscillator,high-power,Yb:YAG,Kerr-lens mode-locked,dual-comb spectroscopy
更新于2025-09-11 14:15:04
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Precipitation of Silver Nanoparticles in Borate Glasses by 1064?nm Nd:YAG Nanosecond Laser Pulses: Characterization and Dielectric Studies
摘要： This work aims to present a modern process to synthesis nanoparticles in a glassy matrix. Borate glasses doped by silver nitrate (AgNO3) via the melt annealing technique were irradiated by a (1064 nm wavelength) Nd:YAG (Neodymium–doped Yttrium Aluminum Garnet) laser to yeild precipitation of silver nanoparticles (AgNPs) in borate glasses. The characterization of the irradiated glasses was investigated using ultraviolet/visible (UV/Vis.), x-ray diffraction (XRD), high resolution-transmission electron microscopy (HR-TEM), ?eld emission-scanning electron microscopy (FE-SEM), and dielectric properties. XRD patterns depict the presence of sharp diffraction peaks at 111 and 200 planes that can be attributed to the precipitated AgNPs in the borate glass sample after laser irradiation. A signi?cant change in color was observed within the borate glass after laser irradiation, which was attributed to the appearance of surface plasmon resonance and con?rmed the presence of AgNPs in the borate glass. The morphological properties and the distribution of the observed AgNPs inside the sample were performed via HR-TEM and FE-SEM. The behavior of dielectric constant and dielectric loss progressively decreased as the frequency increased. The values of AC conductivity increased as the temperature of the borate glass matrix increased.
关键词： Borate,UV/Vis.,Nd:YAG,dielectric properties,AgNPs,XRD,FE-SEM,HR-TEM
更新于2025-09-11 14:15:04
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Predictive Factors for the Efficacy of Er:YAG Laser Treatment of Urinary Incontinence
摘要： Predictive Factors for the Efficacy of Er:YAG Laser Treatment of Urinary Incontinence. Methods: Eighty-two patients with UI were treated by Er:YAG laser in this cohort study. The patients were evaluated by ICIQ-SF and KHQ-UI before and after the procedure. Improvement was categorized as: none (0-25%), mild (26-50%), moderate (51-75%), or high (76-100%). The duration of the treatment effect was evaluated at follow-up in relation to maximum improvement time (MIT) and total improvement time (TIT). Objectives: To determine the efficacy and predictive factors for the success of Er:YAG laser treatment in patients with urinary incontinence (UI). Results: Forty-two patients were determined to have SUI and 40 patients MUI. The mean ISIQ-SF and KHQ-UI scores significantly improved after the procedure (p<0.0001). The SUI patients responded to the laser treatment significantly better (p<0.008). Younger women had significantly better results (p<0.008), while premenopausal women (p<0.032) and women in the early postmenopausal years (p<0.032) also saw a positive response to the Er:YAG laser treatment. Women with a lower BMI had greater improvement (p<0.011). The total laser energy expenditure during the sessions may also be a predictive parameter for the success of Er:YAG laser treatment of UI (p=0.059). MIT and TIT were significantly longer among the patients in the high-improvement group. Conclusion: Er:YAG laser treatment of the symptoms of UI, especially SUI, is more efficacious and of longer duration for younger, premenopausal or early postmenopausal women with normal BMI.
关键词： BMI,Er:YAG Laser,Stress Urinary Incontinence,Age,Menopause
更新于2025-09-11 14:15:04
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Q-PTP is an optimized technology of 1064-nm Q-switched neodymium-doped yttrium aluminum garnet laser in the laser therapy of melasma: A prospective split-face study
摘要： Quickly-pulse-to-pulse (Q-PTP) is the latest dual pulse mode Q-switched neodymium-doped yttrium aluminum garnet [QS Nd:YAG (QSNY)] laser technology that improves efficacy and minimizes side effects. In this study, the safety, efficacy, and advantages of Q-PTP and single-pulse laser mode of 1064-nm QSNY in the treatment of melasma were compared. Twelve healthy women were enrolled in this split-face study. Q-PTP and single-pulse laser mode of 1064-nm QSNY were applied to the treatment side and the control side, respectively. Physician's global assessment, patients' self-assessment and the modified melasma area and severity index (mMASI) scores were used to quantify pigmentation changes. Side effects were recorded. Mean mMASI scores were decreased significantly at the 4th and 12th-week follow-up visit compared to the baseline. Melasma lesion clearance was more than 50% in 58% of patients compared with the baseline. However, both sides of the same patient showed similar therapeutic effect. Minor pain experience and slighter skin erythema reaction were reported in Q-PTP laser mode treatment side compared with the control. No serious complications were found in any of the patients. Q-PTP laser mode of 1064-nm QSNY is an optimal laser therapy in the treatment of melasma with greater safety and superiority.
关键词： laser toning,Q-PTP,1064-nm QS-Nd: YAG laser,melasma
更新于2025-09-11 14:15:04