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High Power 1.5 μm Broad Area Laser Diodes Wavelength Stabilized by Surface Gratings
摘要： Wavelength stabilization against temperature variation of high-power broad area 1.5-μm InGaAsP/InP laser diodes is demonstrated by employing surface gratings. The development targets application in eye-safe automotive LIDAR systems, which would bene?t from deploying narrowband receiver ?lters to block ambient solar radiation for improved signal-to-noise ratio. The surface grating is monolithically integrated on the laser chip using nanoimprint lithography. The peak power of the lasers exceeded 6 W in pulsed mode, for an FWHM spectral width of 0.3 nm and a peak wavelength drift of only 0.1 nm/°C. The wavelength shift with temperature is reduced by ?ve times compared to broad area high-power Fabry–Perot laser diodes typically employed in LIDAR systems.
关键词： high power,distributed Bragg re?ector,LIDAR,Diode lasers
更新于2025-11-28 14:24:03
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A Study of Two Dimensional Tomography Reconstruction of Temperature and Gas Concentration in a Combustion Field Using TDLAS
摘要： Based on tunable diode laser absorption spectroscopy (TDLAS), two-dimensional (2D) distribution reconstructions of gas concentration and temperature are realized using an algebraic reconstruction technique (ART). The influence of the beam distribution and grid size on combustion field reconstruction is investigated to attain optimal reconstruction results with a limited number of beams. Under limited optical-path numbers, it shows that a better spatial resolution is attainable only when the laser beam paths are vertical and parallel to the symmetry axis of the combustion field. Furthermore, experiments with 16 beam paths using one and two flat flame combustion fields are carried out in different fuel-air equivalence ratios under room temperature. The results are in agreement with the simulation results, and the time resolution is less than 1 s.
关键词： tomographic imaging,diode lasers,temperature,spectroscopy,combustion diagnostics,absorption
更新于2025-09-23 15:23:52
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High-gain optical injection locking amplifier in phase-coherent optical frequency transmission
摘要： Optical amplification, which is necessary for extending the distance of optical frequency transfer, has significant impact on the transmission performance. In this paper, we propose a high gain optical injection locking amplifier (OILA) with low phase noise based on optical injection phase-locked loop for the phase-coherent optical frequency transmission. The high gain OILA can provide more than 75 dB gain and ensure that the input carrier frequency fractional stability can reach 8.2 × 10-20 at an averaging time of over 100 s. We then transfer a commercial narrow-linewidth laser over 220 km fiber link with only one amplification step placed at the remote end. After eliminating the noise induced in fiber link, the fractional frequency instability of transferred frequency can reach 9.0 × 10?16 at 1 s and 7.1 × 10?20 at 20000 s.
关键词： Laser injection-locked,Optical standards and testing.,Metrology,Diode lasers
更新于2025-09-23 15:22:29
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High Speed Directly Modulated Fabry-Perot Lasers with an Ultra-Short Cavity Length
摘要： In this study, Fabry-Perot quantum well lasers with shortened cavity designs (25 and 50 μm) were fabricated. The devices had dry-etched and cleaved facets that exhibited an output power of up to 2.36 mW for a cavity length of 25 μm; good spectral performance was achieved. Single-optical-mode operation with better than 25dB of side mode suppression ratio can be achieved for the fabricated devices with 25- and 50-μm cavities. The short-cavity devices also exhibited high-speed modulation at elevated temperatures. Moreover, 25 Gb/s eye diagrams could be obtained at 65oC for the 25 μm device and 55oC for the 50 μm device. Due to their small area, ultra-short-cavity Fabry-Perot laser can be suitably used in next-generation light sources for optical communication.
关键词： Optical device fabrication,Semiconductor lasers,Laser cavity resonators,Amplitude modulation,Diode lasers,Quantum well lasers,Laser modes
更新于2025-09-23 15:21:01
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Diode Laser Spectroscopy for Creating Effective Measuring Systems and Their Use in Biological and Medical Research
摘要： In this paper, we present the most important principles of diode laser spectroscopy, which allow one to create fundamentally new measuring systems for diverse applications in biology and medicine. Using the diode laser spectroscopy method and its primary hardware implementation the emission of gas molecules from skin of the hand was registered and ammonia skin emission was found to be dominant. The properties of exhaled air from patients in different states were determined with another special measuring complex of diode laser spectroscopy. It was shown that when the functional state of the body changes, the gas composition of molecular substances that are present in the exhaled air is altered indirectly and their levels vary significantly depending on the health of the individual. Our findings suggest that it is possible to study the specific functional properties of the human body to facilitate assessment of the health of an individual to determine whether pathological processes occur in the body at various stages of their severity using diode laser spectroscopy. This paper presents clinical and experimental data on this issue.
关键词： non-invasive diagnostics,diode lasers,gas biomarkers,diode laser spectroscopy
更新于2025-09-23 15:19:57
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Outcome of a 980-nm diode laser coagulation in women with radiation-induced hemorrhagic cystitis: a single-center retrospective study
摘要： The purpose of this study was to evaluate the efficacy of a 980-nm diode laser coagulation in women with radiation-induced hemorrhagic cystitis (RHC). We conducted a retrospective study of 21 RHC patients treated with a 980-nm diode laser between July 2014 and December 2017 at our institution. Data was collected with regard to age, sex, lower urinary tract symptoms, use of transfusions, a drop in hemoglobin levels, indication of radiotherapy, median time between radiation therapy and presentation, previous treatments, operative time, mean energy used, number of coagulated areas, catheterization time, discharge time after treatment, hospital stay, and surgical outcome. All 21 patients were women with a median age of 52 years (range 36–68 years). Eighteen patients complained of frequency and urgency, four patients had dysuria, and one patient developed urinary retention. Radiation therapy was primarily indicated in the treatment of cervical cancer in 18 patients (85.7%) and endometrial cancer in three patients (14.3%). Nine patients (42.8%) received blood transfusion before surgery and three patients (14.3%) needed blood transfusion after the procedure. The mean decrease in hemoglobin prior to the procedure was 4.08 ± 2.04 g/dL. The median length of time from completion of radiotherapy to the presentation of hematuria was 38 months (range 8–65 months). All patients had failed an adequate trial of conservative treatment which included adequate hydration, hemostatics, continuous bladder irrigation (CBI), and clot evacuation at the bedside. Eleven patients (52.4%) had previously been treated with endoscopic electrocoagulation; the mean number of procedures was 1.73 ± 0.78 (range 1–3 sessions). Six patients (28.6%) underwent HBO, and sodium hyaluronate solution irrigation was administered to 3 patients (14.3%). The mean number of HBO sessions was 26.3 ± 16.8 (range 8–50), and the mean number of sodium hyaluronate solution irrigation procedures was 4.33 ± 1.53 (range 3–6). All operations were successful. The mean operative time was 45.6 ± 12.3 min, the mean number of coagulated areas was 11.7 ± 4.4, the mean energy used was 2.74 ± 1.14 kJ, the mean catheterization time was 6.2 ± 0.9 days, the mean discharge time after treatment was 6.8 ± 1.2 days, and the average length of a hospital stay was 7.4 ± 1.3 days. In 16 patients (76.2%), hematuria was completely resolved after one session of diode laser coagulation. Four patients (19.0%) underwent multiple sessions of laser treatment due to recurrent gross hematuria (three patients required two sessions and one patient required three sessions). Only one patient (4.8%) who had persistent gross hematuria after diode laser treatment (two sessions) underwent a radical cystectomy, which resolved the hematuria. The median hematuria-free interval of patients who had multiple procedures was 9 months (range 1–13 months). In total, 21 patients underwent 27 sessions of diode laser coagulation, and the median hematuria-free interval was 16 months (range 1–45 months) with a median follow-up of 25 months (range 7–48 months). Our study shows promising results for the management of patients with RHC; however, further evaluation with a larger cohort is required to confirm the efficacy of this treatment.
关键词： Diode lasers,Treatment outcome,Radiotherapy,Cystitis
更新于2025-09-23 15:19:57
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Generation of phase-locked beams by injection locking of extended-cavity diode lasers for atom interferometers
摘要： We report a novel method of generation of two phase-locked beams with a frequency offset at 6.834 GHz. The output of a master laser is modulated by an EOM and further injected into a slave laser that is an extended-cavity diode laser (ECDL). The ECDL amplifies laser power, and filters out unwanted modes (mostly the opposite sideband and the carrier mode) which could interfere Raman transitions and cause laser power fluctuations due to interference effect with the master laser. By injection locking, the slave laser to the first-order sideband of the modulated master laser beam, we achieve a phase noise below ? 50 dBc/Hz at the frequency range between 10 Hz and 100 kHz. The generated phase-locked beams are applicable to light pulse atom interferometers as the Raman lasers.
关键词： extended-cavity diode lasers,phase-locked beams,injection locking,atom interferometers
更新于2025-09-23 15:19:57
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Effect of diode laser application as an adjunct to nonsurgical periodontal therapy on the reduction of red complex microorganisms in type 2 diabetics with chronic periodontitis
摘要： Bactericidal and detoxification effects of diode laser (DL) have been reported in periodontal treatment. The objective of this study was investigating the additional effect of DL with nonsurgical periodontal treatment on the red complex bacteria in type 2 diabetes mellitus (DM) patients with chronic periodontitis (CP). Sixty type 2 DM patients with chronic periodontitis (CP) were randomly assigned in two parallel groups to receive scaling root planning (SRP, n = 30) or SRP followed by DL periodontal pocket irradiation (SRP + DL, n = 30). Recording of clinical parameters and subgingival plaque sampling were performed at baseline, and post therapy (1 and 3 months after treatment). Amounts of Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia were evaluated with quantitative RT-PCR. Significant reductions for numbers of all three bacterial species were observed at 1 and 3 months compared with baseline for both treatments (p < 0.001), but no significant differences were found between two groups regarding bacterial reductions at these follow-up time points. No additional benefit of DL as an adjunct to nonsurgical periodontal therapy was recognized in the reduction of P. gingivalis, T. denticola, and T. forsythia for type 2 DM patients with CP. Further studies are required to clarify the effects of diode laser on the other periodontopathogens.
关键词： Nonsurgical periodontal treatment,Periodontopathogens,Diabetes mellitus,Diode lasers,Chronic periodontitis
更新于2025-09-23 15:19:57
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Watt-Level CW Ti:Sapphire Oscillator Directly Pumped with Green Laser Diodes Module
摘要： A watt-level directly diode-pumped continuous-wave (CW) Ti:Sapphire oscillator was demonstrated for the first breakthrough by a high-power green laser-diode-pumped module employing the technologies of beam shaping, beam collimation, polarization beam combining, and fiber coupling. A 1.36-W output power and 10.6% of slope efficiency were obtained based on the double-concave (DC) cavity configuration. This is the highest CW output power from Ti:Sapphire (Ti:S) oscillator directly pumped by green laser diodes (LDs) reported so far.
关键词： Semiconductor laser arrays,Optical pumping,Optical design techniques,Diode lasers
更新于2025-09-19 17:13:59
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[IEEE 2019 IEEE High Power Diode Lasers and Systems Conference (HPD) - Coventry, United Kingdom (2019.10.9-2019.10.10)] 2019 IEEE High Power Diode Lasers and Systems Conference (HPD) - Simulation of the slow-axis beam properties of broad-area lasers and its use in the development of high-brightness sources
摘要： The objective of this work is to demonstrate that the slow-axis beam properties of broad-area diode lasers can be predicted by numerical modeling and that the results guide design decisions in the semiconductor laser development. We present a numerical study for 6 different semiconductor laser single emitter designs and compare the computed results to experimental values. The devices differ in width of the contact opening, cavity length, position and depth of an index trench, and facet re?ectivity.
关键词： Semiconductor Lasers,Index-Guided,Beam Propagation Method,Lasers,Modeling,Gain-Guided,Frequency Domain,Simulation,Thermal Lens,Diode Lasers,Broad-Area
更新于2025-09-16 10:30:52