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Effect of Er:YAG laser on debonding strength of laminate veneers
摘要： Objective: The purpose of this study was to evaluate the debonding strength of laminate veneers after using erbium?doped: yttrium aluminium garnet (Er:YAG) laser. Materials and Methods: A total of 60 bovine mandibular incisor teeth were divided into two groups (n = 30). Cylindrical specimens (0.7 mm × 5 mm) were fabricated from Empress II ceramic. Then, they were cemented to incisors using dual?cured resin cement (Variolink II). In the first group, no laser application was performed. The Er:YAG laser was applied on each laminate veneer at the test group for 9 s by using the scanning method. Shear force to remove the laminate veneers were applied with universal testing machine at a crosshead speed of 1 mm/min. Results: Results of this study exhibited significant differences between the control (27.28 ± 2.24 MPa) and test group (3.44 ± 0.69 MPa) (P < 0.05). Conclusion: This study shows that application of Er:YAG laser decreased the bond strength of laminate veneers.
关键词： Debonding,shear bond strength,scanning method,erbium-doped:yttrium aluminium garnet laser,laminate veneers
更新于2025-09-16 10:30:52
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Optical Fiber Communications (Principles and Applications) || Optical Amplifiers
摘要： An optical amplifier is a widely used device in optical fiber communications for the purpose of amplification of the optical signal generated by an optical transmitter. The optical signal is directly amplified to yield optical signal without any conversion to electrical signal first and then restoring it to amplified optical signal. This implies that optical amplifiers operate on photons in all-optical domain. In essence, optical amplifiers do require source and photodetector as optoelectronic devices and additional electronic circuits for other operations such as shaping of optical pulses including retiming. But why do we need optical amplifiers? We know that typical fiber loss around 1500-nm wavelength is approximately 0.2 dB/km. Let us examine what happens after the optical signals travel about 100 km down the fiber. The signals are attenuated by 20 dB. So they need to be amplified, otherwise the signal-to-noise ratio of detected signals is too low and bit-error-rate becomes too high (typically desired value of BER is <10-9). One way to resolve this issue is to detect the weak signals, followed by modulating a new laser (optical-to-electrical-to-optical conversions) which requires high-speed (>10 GHz) electronic circuitry. Therefore, the best way to amplify the signal is only optically and the preferred method is fiber amplifier which is the most efficient, the most stable and the one with the lowest loss.
关键词： Erbium-doped fiber amplifiers,Raman fiber amplifiers,optical amplifiers,semiconductor optical amplifiers,optical fiber communications
更新于2025-09-12 10:27:22
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Numerical study of complex dynamics and extreme events within noise-like pulses from an erbium figure-eight laser
摘要： Some complex dissipative dynamics associated with the noise-like pulse (NLP) regime of a passively mode-locked erbium-doped ?ber laser are studied numerically. By means of a convenient 3D mapping of the spatio-temporal pulse evolution, for properly chosen dispersion parameters, several puzzling dissipative dynamics of NLPs are identi?ed, including the expelling of sub-packets that move away from the main bunch, the sudden extinction of isolated sub-pulses, the collision between di?erent internal fragments travelling at di?erent speeds, the rising of sub-pulses, the formation of complex trajectories by substructures that ?rst move away and then return to the main bunch, and so on. In addition, the emergence of optical rogue waves (ORWs) within NLPs is also demonstrated numerically; to help understand these behaviors evidenced in the time domain, spectral analyzes were also performed that show, among other things, that the spectrum of a NLP is notoriously distorted when it hosts an ORW phenomenon. These numerical results are consistent with previously published experimental results.
关键词： erbium-doped ?ber laser,dissipative dynamics,noise-like pulse,optical rogue waves
更新于2025-09-12 10:27:22
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Assessment of microcracks and shear bond strength after debonding orthodontic ceramic brackets on enamel priorly etched by different Er,Cr:YSGG and Er:YAG laser settings without acid application: An in vitro study
摘要： Background data > Enamel microcrack formation has a high incidence after mechanical debonding of ceramic brackets. This may be due to high delivered shear bond strength values when enamel is priorly etched by phosphoric acid. It is still not well elucidated in the literature if laser etching affects enamel the same way. The aim of the research was to analyze different Er,Cr:YSGG and Er:YAG laser etching settings as an alternative to phosphoric acid, in an attempt to prevent enamel microcrack formation during laser etching and mechanical debonding, while reducing the shear bond strength to the minimal clinical acceptable value. Materials and methods > One hundred and thirty-three teeth were randomly divided into 7 experimental groups according to their etching modalities. Settings used for enamel etching were in Er,Cr:YSGG groups: Er,Cr:YSGG (1.5 Watt, W/20 Hertz, Hz); Er,Cr:YSGG (1.5 W/15 Hz) and Er,Cr:YSGG (2 W/20 Hz) and settings used for enamel etching in Er:YAG groups were: Er:YAG (60 millijoules , mJ), Er:YAG (80 mJ) and Er:YAG (100 mJ). Group C etched with 37% phosphoric acid served as control. Microscopic analysis was performed to assess presence of enamel microcracks. Shear bond strength was evaluated after thermocycling using Weibull survival analysis. Results > All groups showed a reduction in additional microcracks after debonding when compared to control, but only group Er:YAG (60 mJ) exhibited a statistically significant difference. Groups Er:YAG (80 mJ), control and Er:YAG (100 mJ) showed respectively the highest probability of survival at various stress levels followed by groups Er:YAG (60 mJ); Er,Cr:YSGG (1.5 W/15 Hz); Er,Cr:YSGG (2 W/20 Hz) and Er,Cr:YSGG (1.5 W/20 Hz) that presented a relatively considerable risk of failure, even at low stress levels.
关键词： Shear bond strength,Microcracks,Etching,Erbium laser
更新于2025-09-12 10:27:22
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An Erbium-Doped Fiber Whispering-Gallery-Mode Microcavity Laser
摘要： A kind of whispering-gallery-mode (WGM) micro-cavities has been fabricated by melting a corroded erbium-doped fiber with a fiber-fusion splicer. The quality factor (Q) value of the microcavity can reach as high as 3×107. The microcavity is pumped by a wavelength-tunable laser source, and due to the high-Q characteristics, the laser threshold can be as low as 21.2 μW in a 60-μm-diameter microsphere-like cavity. By tuning the frequency of the pump laser at 1485 nm with 19.6 GHz, we can tune the WGM microcavity laser by 17.3 GHz around 1578.25 nm.
关键词： Erbium,whispering gallery mode (WGM),microcavity,microlaser
更新于2025-09-12 10:27:22
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All-Fiber Erbium-doped Q-Switched Laser with Recycled Graphite Oxide
摘要： This work demonstrates a passively Q-Switched fiber laser employing graphite oxide as a saturable absorber, generating tunable microsecond pulses with kHz repetition rates, pulse energies of up to 15.54 nJ and the pulse-to-pulse timing jitter of 46.14 fs. The graphite oxide samples were obtained by recycling the graphite present in Li-ion batteries utilized in cell phone devices through a chemical separation and subsequent oxidation process. Sample characterization employing X-ray diffraction, solid-state nuclear magnetic resonance and Raman spectroscopy showed that the produced graphite oxide exhibited a homogeneously oxidized structure. These results indicate that applications in the physics of pulsed lasers can benefit from the recycling of lithium batteries, directing the process of discarding spent batteries.
关键词： Recycled Graphite Oxide,Lithium Batteries,Erbium-Doped Fiber Laser,Saturable Absorber,Q-Switched
更新于2025-09-12 10:27:22
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Use of Er:YAG laser in the treatment of vulvar lichen sclerosus
摘要： Objective: The aim of this research was to evaluate the efficacy and safety of Er:YAG lasers to improve signs and symptoms of vulvar lichen sclerosus. Methods: The study population consisted of 28 women with symptomatic vulvar lichen sclerosus. Three nonablative, thermal-only Er:YAG laser treatment sessions (7 J/cm2, 2 Hz, 7 mm spot) were performed at 4-week intervals. Each patient was asked about the presence of symptoms, such as itching, pain, and coital pain. Clinical diagnosis was established on the basis of the presence of lesions such as hypopigmentation, ecchymosis, hyperkeratosis, excoriations, or fissures. The affected areas were divided by zones (clitoris, introitus, labia minora, labia majora, perineum, labial fusion, and effacement) and were visually evaluated. Based on the presence of symptoms, lesions, and affected zones, a scale with a maximum of 14 scores was established for use before and after treatment. The impact of lichen sclerosus on patients' lives before and after treatment was evaluated with an 11-point visual analogue scale, and treatment discomfort was assessed at each session. Results: After analysis of each scoring component, individual statistically significant reductions were observed in itching, pain, ecchymosis, excoriations, and hypopigmentation. Conclusion: The Er:YAG laser is a safe, well tolerated, and effective method for the adjuvant treatment of vulvar lichen sclerosus. Three sessions with monthly intervals using the indicated parameters can quantifiably reduce the impact of lichen sclerosus on patients' lives.
关键词： erbium laser,vulvar lichen sclerosus
更新于2025-09-12 10:27:22
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Erbium:YAG laser treatment of female stress urinary incontinence: midterm data
摘要： Introduction and hypothesis Stress urinary incontinence (SUI) is treated using intravaginal laser therapy. We wanted to find out how incontinence severity at baseline and the number of laser interventions affect success rate, and whether the effect of laser therapy was obvious 6 months and 2 years after the last laser intervention. Methods Fifty-nine women, 32 with SUI I, 16 with SUI II, and 11 with SUI III were treated using an erbium-doped yttrium aluminium garnet (Er:YAG) laser following the IncontiLase? protocol. Therapy included five laser sessions with a 1-month interval between sessions. Objective (1-h pad test) and subjective data (International Consultation on Incontinence Questionnaire-Urinary Incontinence Short Form [ICIQ-UI SF], Pelvic Organ Prolapse/Urinary Incontinence Sexual Questionnaire [PISQ-12]) were assessed at baseline, after two and four laser sessions and 6 months and 2 years after the fifth laser session. Results Objective cure/improve rates for mild SUI I were 69%, 78%, 91%, and 78% after two, four, and five laser sessions at the 6-month and 2-year follow-ups. Subjective cure rates (ICIQ-UI SF) were 53%, 69%, 72%, and 66%, and sexual function (PISQ-12) also improved. For SUI II, objective cure/improve rates were 31%, 63%, 69%, and 50%. Subjective cure rate was 13% at the 2-year follow-up. For SUI III, only one patient had an objective improvement after two and four laser sessions. Conclusions Intravaginal laser therapy led to cure/improvement for SUI I and SUI II, but not for severe SUI III. Outcome was better after four to five laser sessions than after two laser sessions. Follow-up data 6 months and 2 years after laser intervention showed sustainability of the treatment.
关键词： ICIQ-UI SF,1-h pad test,Stress urinary incontinence,Intravaginal laser therapy,Erbium:YAG laser,Non-ablative SMOOTH mode
更新于2025-09-12 10:27:22
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Tapered erbium-doped fibre laser system delivering 10 MW of peak power
摘要： We consider a fibre laser system generating ~10-mJ, ~500-fs pulses with a peak power of ~10 MW at a repetition rate of 100 kHz and emission wavelength of 1.56 mm. The system is based on a master oscillator – power amplifier configuration. The amplifier ensures chirped-pulse amplification. The pulses are then compressed by a dispersive grating compressor. The output amplifier stage is based on a specially designed tapered large mode area erbium-doped fibre for suppressing nonlinear effects. The experimental data agree with numerical simulation results for the stretcher, amplifier and compressor. The stretcher and amplifier have been simulated using a generalised nonlinear Schr?dinger equation. In addition, numerical simulation results suggest that optimising the stretcher and compressor will potentially allow the peak power of the system to be scaled up to ~30 MW.
关键词： erbium-doped fibre amplifiers,tapered fibre,dispersive grating compressor,high peak power fibre laser systems,chirped-pulse amplification
更新于2025-09-12 10:27:22
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Genitourinary syndrome of menopause (GSM) and laser VEL: a review
摘要： The purposeof this publication is to summarize the results of the vaginal erbium:yttrium-aluminum-garnet (Er:YAG) Smooth? laser (VEL) on the vaginal atrophy component of the genitourinary syndrome of menopause (GSM). GSM has two categories of clinical signs related to estrogen deficiency: symptoms of vulvovaginal atrophy (VVA) and urinary symptoms. This symptomatology is chronic, progressive over the years and affects a majority of women concerned by natural menopause but not exclusively: we must also consider the growing number of survivors of gynecological or non-gynecological cancers (breast, cervix, uterus, vagina, anus, etc.). At a time when hormonal treatment of menopause is contested as is the installation of under urethra prosthesis, the innovation provided by the VEL technology has the merit of offering the women concerned an effective therapeutic alternative with the security of a patent. The VEL technology has an original and unique process: acting only by thermal effect and not by ablation on tissue, VEL is a safe solution in terms of side effects and potential complications. Studies have been increasing since 2012 and all demonstrate a significant improvement in the GSM signs and symptoms, as well as an improved sexual life after VEL treatment. Double-blind, placebo-controlled, randomized studies are expected in order to ultimately confirm the safety and effectiveness of VEL.
关键词： dyspareunia,genitourinary syndrome of menopause,gynecological cancers,collagen,vaginal atrophy,menopause,laser erbium Smooth?
更新于2025-09-12 10:27:22