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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) - Passively Mode-Locked High-Repetition Rate Er:YLF Laser at 2.81 μm Generating 72 ps Pulses
摘要： The erbium-doped active media allow to generate laser radiation in spectral range 2.7-2.94 μm if the laser transition 4I11/2→4I13/2 is used. Since the laser radiation in this spectral range is strongly absorbed in the water these lasers can be used in medicine (surgery, ophthalmology, urology). Nowadays, there are many papers deal with erbium-doped bulk active media operating in free-running or Q-switched regime, nevertheless, the passively mode-locked lasers are mainly built with Er-doped fibres. However, the compact passively mode-locked erbium-doped bulk lasers could offer a higher repetition rate and smaller dimensions. To date, the shortest laser pulses (1.78 ns) generated with erbium bulk laser (Er:CaF2-SrF2) was obtained in Q-switched mode-locked regime. In this paper, the SESAM mode-locked compact Er:YLF laser with the picosecond pulses and GHz repetition rate for the first time, according to the author’s knowledge, is presented.
关键词： mode-locked,GHz repetition rate,picosecond pulses,laser,erbium-doped
更新于2025-09-11 14:15:04
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Fractional dynamics of an erbium-doped fiber laser model
摘要： In this paper we investigate the model of the time-fractional dynamics of an erbium-doped fiber laser model (TFDEFL) with Liouville–Caputo (LC), Caputo–Fabrizio–Caputo (CFC) and Atangana–Baleanu–Caputo (ABC) time-fractional derivatives. We employ the homotopy analysis transform method (HATM) to calculate approximate solutions for the TFDEFL model. This method gives the solution in the form of a rapidly convergent series that can ensure the convergence in solving the resultant series. We study the convergence analysis of HATM by computing the interval of convergence through the h-curves, the residual error function and the average residual error, respectively. We also show the effectiveness and accuracy of this method by comparing the approximate solutions based upon the LC, CFC and ABC time-fractional derivatives.
关键词： Erbium-doped fiber laser model,Fractional calculus,Fractional derivatives,Analytical solutions,Homotopy analysis transform method
更新于2025-09-11 14:15:04
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The effect of 1540‐nm fractional erbium‐glass laser in the treatment of androgenic alopecia
摘要： Background: Androgenic alopecia is common, chronic dermatologic disorder. A variety of lasers and light sources appear to be safe and effective in the treatment of AGA. Aims: To evaluate the efficacy and safety of 1540‐nm fractional erbium glass laser in the treatment of AGA. Patients/Methods: This was an interventional therapeutic study for the treatment of patients with AGA. The patients received 10 sessions with 1540‐nm fractional erbium glass laser at 2‐week intervals. The assessment of the response was done before and at the end of follow‐up period, both objectively (the change in the density of terminal hair and the diameter of the hair shaft) and subjectively (patient satisfaction). Any adverse effects were documented during the study. Results: Forty‐seven out of 51 patients completed the study. After 5 months of laser treatment, the density of hair and hair thickness was significantly increased in both males and females (P value .001). Conclusion: The 1540‐nm fractional erbium‐glass laser seems to be an effective and safe option for treatment of patients with AGA. The improvement was accomplished in a short period.
关键词： fractional,laser,1540 nm,androgenic alopecia,erbium‐glass
更新于2025-09-11 14:15:04
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Er:YAG laser vs. sharp debridement in management of chronic wounds: Effects on pain and bacterial load
摘要： Chronic wounds affect roughly 6.5 million patients in the United States annually. Current standard of therapy entails weekly sharp debridement. However, the sharp technique is associated with significant pain, while having minimal impact on the bioburden. Our study proposes the Er:YAG laser as an alternative method of debridement that may decrease procedural pain, reduce bioburden, and potentially improve overall healing. This pilot study was performed as a prospective, randomized, controlled, crossover clinical trial, containing two groups: 1) one group underwent single laser debridement session first, followed by single sharp debridement session one week later; 2) the other group underwent single sharp debridement session first, followed by single laser debridement session one week later. Variables analyzed included pain during debridement, pre- and post-debridement wound sizes, pre- and post-debridement bacterial loads and patient preference. Twenty-two patients were enrolled (12 patients in Group 1, plus 10 patients in Group 2). The mean pain score for patients undergoing laser debridement was 3.0 ± 1.7 versus 4.8 ± 2.6 for those undergoing sharp debridement (p = 0.003). The mean percent change in wound size one-week post-laser debridement was -20.8% ± 80.1%, as compared with -36.7% ± 54.3% one-week post-sharp debridement (p = 0.6). The percentage of patients who had a bacterial load in the Low/Negative category increased from 27.3% to 59.1% immediately after laser debridement (p = 0.04), versus 54.5% to 68.2% immediately after sharp debridement (p = 0.38). Moreover, there was a sustained decrease in bacterial load one-week post-laser debridement, as compared with no sustained decrease one-week post-sharp debridement (p < 0.02). Overall, 52.9% of patients preferred laser debridement versus 35.3% for sharp debridement. We believe that Er:YAG laser serves as a promising technology in chronic wounds, functioning as a potentially superior alternative to sharp debridement, the current standard of therapy.
关键词： chronic wounds,laser,erbium,chronic ulcers,debridement
更新于2025-09-11 14:15:04
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Efficacy of erbium-doped yttrium aluminum garnet laser with casein phosphopeptide amorphous calcium phosphate with and without fluoride for remineralization of white spot lesions around orthodontic brackets
摘要： Objective: This study aimed to assess the efficacy of erbium?doped yttrium aluminum garnet (Er:YAG) laser, pastes containing casein phosphopeptide amorphous calcium phosphate (CPP?ACP) with and without fluoride and their combination for prevention of white spot lesions in the enamel. Materials and Methods: This in vitro experimental study was conducted on 90 extracted sound premolars. The teeth were then randomly divided into six groups of 15: (1) Control, (2) laser, (3) CPP?ACP with fluoride (GC MI Paste, Recaldent? 900 ppm as NaF), (4) CPP?ACP without fluoride (GC Tooth Mousse Recaldent?), (5) laser + CPP?ACP with fluoride, and (6) laser + CPP?ACP without fluoride. In each group, enamel surface was exposed to the remineralizing agent. The teeth were then subjected to pH cycling for 14 days. The teeth were then sectioned, polished, and underwent cross?sectional microhardness testing at 20–160 μ depth quantitatively. Using the Simpson’s rule, the amount of mineral loss was calculated in each group. Statistical Analysis Used: ANOVA was used for the comparisons, and Tukey’s test was applied for pairwise comparisons. Results: The highest mean volume percentage of microhardness at 20–60 μ depth belonged to the group laser + CPP?ACP with fluoride and the lowest belonged to the control group (P = 0.001). The differences were not significant at 80?120 μ depth (P > 0.05). These finding are confirmed according to ?Z (mineral loss). Conclusion: Based on these results, Er: YAG laser was able to decrease demineralization and was a potential alternative to preventive dentistry and was more effective when combined with CPP?ACP products.
关键词： Casein phosphopeptide amorphous calcium phosphate,white spot lesion,erbium-doped yttrium aluminum garnet 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) - Tunable Near 3-μm Difference Frequency Generation using Ytterbium and Broadband Seed Erbium Fiber Lasers
摘要： The absorption peaks corresponding to vibrational energy levels of various molecules are located in the mid-infrared (mid-IR) spectral range. For instance, the interatomic bonding of hydrogen and another heavier element (e.g. C-H, O-H, N-H) that is a part of some organic and inorganic molecules is characterized by the absorption peak located near 3μm wavelength. Laser sources operating at this wavelength can be useful tools for medical applications, non-metallic materials processing, and spectroscopy [1]. The study of the interaction of various organic substances with mid-IR radiation is rather challenging because of their great diversity and chemical composition complexity. An application of the laser source with high output power and tunable wavelength can significantly facilitate possible investigation problems [2,3]. This research is devoted to the elaboration of the tunable laser source of mid-IR radiation using single pass difference frequency generation of the pump (1.03 μm) and seed (1.55 μm) radiation in periodically poled lithium niobate (PPLN) crystal (see Fig.1 (a)). Pulsed ytterbium and erbium fiber lasers were used as the pump and seed radiation sources respectively. Both of them were assembled basing on a MOPA optical scheme, pulse duration was about 2 ns and repetition rate was 3 MHz. The average output power of Yb-laser was up to 50 W, which is five times higher than the maximum power of Er laser source. The wavelength corresponding to the difference frequency generation for these fiber lasers lies in the 3 μm region. The spectrum of the seed radiation was considerably broadened in the delivery fiber due to the four-wave mixing and Raman scattering. So that, it was possible to obtain the seed radiation in the spectral range from 1.55 m to 1.60 μm. The selective parametric amplification region of seed radiation can be shifted by changing PPLN temperature, as a result, the idler radiation wavelength tuning was achieved. We obtained the idler tuning in 2.9–3.1 μm wavelength range by changing the PPLN temperature from 45 °C to 110 °C. This tuning range was restricted by the spectral width of the Er-laser radiation. The idler radiation power varied from 5.5 W to 8.0 W in the whole tuning range (see Fig.1 (b)). The conversion efficiency reached 15% in respect to the Yb-laser power. As we were not able to measure directly the mid-IR radiation spectrum but it was derived using the experimentally measured spectrum of the amplified seed radiation. Normalized calculation results are shown in Fig.1 (c). The spectral width of the output mid-IR radiation reached 20-30 nm (at a 3 dB FWHM level).
关键词： tunable laser source,mid-infrared,difference frequency generation,PPLN crystal,erbium fiber laser,ytterbium fiber laser
更新于2025-09-11 14:15:04
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The effect of vaginal erbium laser treatment on sexual function and vaginal health in women with a history of breast cancer and symptoms of the genitourinary syndrome of menopause
摘要： Objectives: To assess the effects of vaginal erbium laser treatment on the vaginal health and sexual function of postmenopausal women with a history of breast cancer. Methods: An open, prospective, therapeutic intervention study was conducted with 24 postmenopausal women with a history of breast cancer and vaginal dryness, and/or dyspareunia, who had not used vaginal hormone therapy for at least 6 months. The women were treated using a 2,940-nm Erbium: YAG laser (Etherea-MX, Athena, Sa?o Carlos, Sa?o Paulo, Brazil), with 90o and 360o scanning scopes, between August, 2017 and October, 2017 in a private clinic in a city of southeastern Brazil. Vaginal erbium laser treatment was performed at three sessions with a 30-day interval between each session. Sexual function was assessed before and 1 month after treatment using the Short Personal Experiences Questionnaire. Questions related to genitourinary symptoms were also applied. Vaginal health was assessed before each laser session using the Vaginal Health Index Score. Results: Mean age was 53.7 years. Vaginal health improved, as shown by an increased overall score (P < 0.001). The effect size was large between pretreatment and post-treatment scores for vaginal elasticity, fluid volume, epithelial integrity, and moisture. The effect size was also significant for the overall sexual function score and for the score in the dyspareunia domain between pretreatment and 1 month after the final treatment session. Conclusion: Vaginal erbium laser may represent a novel therapeutic option for improving vaginal health and sexual function in postmenopausal women with a history of breast cancer.
关键词： Sexual function,Vulvovaginal atrophy,YAG laser,Dyspareunia,Menopause,Breast cancer,Erbium
更新于2025-09-11 14:15:04
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74.38 Tb/s Transmission Over 6300 km Single Mode Fibre Enabled by C+L Amplification and Geometrically Shaped PDM-64QAM
摘要： Ultrawide-bandwidth optical amplification over almost 90 nm, covering the C+L bands, is described. Complemented by system-tailored geometrical constellation shaping and nonlinearity compensation, it enabled a record capacity transmission of 74.38 Tb/s over 6,300 km of G.654 single-mode fibre. The hybrid scheme, combining backward Raman pre-amplification with EDFA, significantly improves the average effective noise figure across the entire bandwidth, allowing the use of span lengths of 70 km. The system-tailored GS-64QAM constellation was optimised to both linear link impairments and transceiver nonlinearities, improving the gap to the AWGN channel capacity relative to square 64QAM from 0.6 bit/symbol to 0.35 bit/symbol. We experimentally evaluated the system performance using the bit-wise achievable information rate (AIR) and signal-to-noise ratio (SNR) at the end of transmission, as well as post SD-FEC BER.
关键词： geometric constellation shaping,nonlinear compensation,Erbium-doped fibre amplifier,Raman amplification,Broadband C+L band transoceanic transmission
更新于2025-09-11 14:15:04
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[IEEE 2019 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Sao Paulo, Brazil (2019.10.7-2019.10.9)] 2019 SBFoton International Optics and Photonics Conference (SBFoton IOPC) - Few-Mode Erbium-Doped Fiber Amplifier Design Challenges for WDM Optical Networks
摘要： The use of optical spatial division multiplexing (SDM) technologies increases the capacity of the optical channel, allowing higher transmission rates than those observed in wavelength division multiplexing (WDM) optical systems based on single-mode fibers. In particular, spatial multiplexing based on multimode fibers allows the transmission of information in orthogonal modes. In these systems, the erbium-doped fiber amplifier (EDFA) remains essential to compensate for optical link losses. This paper presents the challenges to the development of EDFAs for WDM optical systems based on few-mode fibers, considering the addition of gain flattening filters and correction of gain calculation.
关键词： erbium-doped fiber amplifiers,space division multiplexing,gain equalization,Few-mode fiber amplifier
更新于2025-09-11 14:15:04
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Handbook of Graphene || Ultrashort Pulse Fiber Laser Generation Using Molybdenum Disulfide and Tungsten Disulfide Saturable Absorber
摘要： Passive mode-locked erbium-doped fiber lasers (EDFLs) based on the newly developed tungsten disulfide (WS2) and molybdenum disulfide (MoS2) saturable absorber (SA) are experimentally demonstrated. The laser cavity has a total length of 204 m long with a 2.4-m-long erbium-doped fiber (EDF) as a gain medium, and thus it operates in anomalous fiber dispersion of -4.44 ps2. With a WS2 SA, a stable 2.43 ps soliton pulse operating at 1562-nm wavelength with the third harmonic repetition rate of 3.48 MHz is successfully obtained. Mode-locked pulse is realized at threshold pump power of 184 mW with calculated maximum pulse energy as 2.0 nJ at a pump power of 249.6 mW, respectively. Furthermore, the fabricated MoS2 SA can also work steadily at mode-locking state with the pump power range from 105 to 140 mW. The MoS2-based EDFL operates at 1566 nm with the fundamental frequency of 1.16 MHz and pulse width of 468 ns. Compared to WS2-based laser, this laser produces a higher pulse energy of 9.13 nJ. These results show that both WS2 and MoS2 SAs are simple and indicate low-insertion-loss, low-cost, and ultrafast saturable absorption device for ultrafast photonic applications. Various applications may benefit from the ultrafast nonlinear features of these transition-metal dichalcogenide (TMD) materials.
关键词： mode-locking technique,Erbium-doped fiber,saturable absorber
更新于2025-09-11 14:15:04