17,484 results match your criteria fiber laser

Handheld laser-fiber vibrometry probe for assessing auditory ossicles displacement.

J Biomed Opt 2021 Jul;26(7)

Univ. Opolski, Poland.

Significance: Measurements of auditory ossicles displacement are commonly carried out by means of laser-Doppler vibrometry (LDV), which is considered to be a gold standard. The limitation of the LDV method, especially for in vivo measurements, is the necessity to expose an object in a straight line to a laser beam operating from a distance. An alternative to this approach is the use of a handheld laser-fiber vibrometry probe (HLFVP) with a curved tip. Read More

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Use of 1,470 nm laser for treatment of superficial venous insufficiency.

J Vasc Bras 2021 25;20:e20200244. Epub 2021 Jun 25.

Clínica Coris Medicina Vascular do Baía Sul Medical Center, Florianópolis, SC, Brasil.

Background: There are several ways to treat varicose veins of the lower limbs, among which use of 1470nm diode lasers stands out. This technique can be used to treat patients in outpatient settings, with early return to work, good esthetic results, and low rates of complications. However, variables such as the laser wavelength, the power administered in each area, the type of fiber, and the linear intravenous energy density (LEED) are still extensively discussed. Read More

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Upper-lip laser frenectomy with a diode laser in a pediatric patient: a case report.

J Biol Regul Homeost Agents 2021 May-Jun;35(3 Suppl. 1):29-35

Department of Chemical Science and Technologies, Dentistry, University of Rome "Tor Vergata", Rome, Italy.

The case report aims to describe the parameters of performing upper labial frenectomy with the use of diode laser beams without infiltrated local anaesthesia. A 6-year-old patient was referred by the orthodontist for assessment of the upper anterior labial frenum. The dental treatment plan reported only the presence of caries on deciduous teeth and seals on the first permanent molars. Read More

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Preparation and Characterization of Electrospun Polylactic Acid (PLA) Fiber Loaded with Birch Bark Triterpene Extract for Wound Dressing.

AAPS PharmSciTech 2021 Jul 20;22(6):205. Epub 2021 Jul 20.

Department of Pharmaceutical Technology, University of Tübingen, Auf der Morgenstelle 8, D-72076, Tübingen, Germany.

Drug-loaded electrospun fibers have attracted increasing attention as a promising wound dressing material due to their capability of preventing from infections and inflammation and maintaining an appropriate environment for wound healing. In this study, polylactic acid (PLA), which is widely used in wound management, was chosen as electrospinnable polymer. A triterpene extract (TE) from the outer bark of birch known for its anti-inflammatory, antiviral, antibacterial, and wound healing effects was chosen to produce TE-loaded PLA electrospun fibers for wound dressing. Read More

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Ultra-Highly Sensitive Ammonia Detection Based on Light-Induced Thermoelastic Spectroscopy.

Yao Mi Yufei Ma

Sensors (Basel) 2021 Jul 2;21(13). Epub 2021 Jul 2.

National Key Laboratory of Science and Technology on Tunable Laser, Harbin Institute of Technology, Harbin 150001, China.

This invited paper demonstrated an ultra-highly sensitive ammonia (NH) sensor based on the light-induced thermoelastic spectroscopy (LITES) technique for the first time. A quartz tuning fork (QTF) with a resonance frequency of 32.768 kHz was employed as a detector. Read More

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Effects of Vanadium on the Structural and Optical Properties of Borate Glasses Containing Er and Silver Nanoparticles.

Materials (Basel) 2021 Jul 2;14(13). Epub 2021 Jul 2.

Faculty of Applied Sciences, Universiti Teknologi MARA, UiTM, Shah Alam 40450, Selangor, Malaysia.

The erbium-vanadium co-doped borate glasses, embedded with silver nanoparticles (Ag NPs), were prepared to improve their optical properties for potential optical fiber and glass laser application. The borate glasses with composition (59.5-) BO-20NaO-20CaO-VO-ErO-0. Read More

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Current status of Thulium Fiber Laser (TFL) lithotripsy: An up-to-date review.

BJU Int 2021 Jul 17. Epub 2021 Jul 17.

Department of Urology, Haukeland University Hospital, Bergen, Norway.

Introduction: Thulium Fiber Laser (TFL) is the latest laser technology, which has gained increased attention for its role in stone lithotripsy. Findings from in vitro studies have shown that it can potentially deliver reduced retropulsion and efficient stone clearance. A number of clinical studies on TFL have now been reported. Read More

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Radiation-Balanced Silica Fiber Amplifier.

Phys Rev Lett 2021 Jul;127(1):013903

Edward L. Ginzton Laboratory, Stanford University, Stanford, California 94305, USA.

We report what we believe to be the first radiation-balanced fiber amplifier-a device that provides optical gain while experiencing no temperature rise. The gain medium is a silica fiber with a 21-μm-diameter core highly doped with Yb^{3+} (2.52 wt. Read More

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Adopting MR-guided stereotactic laser ablations for epileptic lesions: initial clinical experience and lessons learned.

Acta Neurochir (Wien) 2021 Jul 16. Epub 2021 Jul 16.

Functional Neurosurgery Unit, Department of Neurosurgery, Tel-Aviv Medical Center, Tel-Aviv, Israel.

Objective: MR-guided laser interstitial thermal therapy (MRgLITT) is a minimally invasive technique for ablating brain lesions under real-time MRI feedback and control of the ablation process. The Medtronic Visualase system was recently approved for use in Europe and Israel. We report our initial technical experience using the system in the first 16 cases in which the system was used to ablate focal epileptogenic lesions. Read More

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Comparison of Different Pulse Modulation Modes for Holmium:YAG Laser Lithotripsy Ablation in a Benchtop Model.

J Endourol 2021 Jul 16. Epub 2021 Jul 16.

Duke University Medical Center, 22957, Division of Urology, Durham, North Carolina, United States;

: Manipulation of Holmium:YAG (Ho:YAG) laser parameters such as pulse energy, frequency, and duration can impact laser lithotripsy ablation efficiency. In 2017, Lumenis introduced Moses™ Technology which uses pulse modulation to enhance the delivery of energy from fiber to stone as well as to minimize stone retropulsion. Since the introduction of Moses™ Technology, other companies have brought additional pulse modulation concepts to market. Read More

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High-precision passive stabilization of repetition rate for a mode-locked fiber laser based on optical pulse injection.

Opt Express 2021 Jun;29(13):20930-20940

We have proposed and implemented a novel scheme to obtain high-precision repetition rate stabilization for a polarization-maintaining mode-locked fiber laser. The essential technique lies in the periodic injection of electronically modulated optical pulses into a nonlinear amplifying loop mirror within the laser resonator. Thanks to the nonlinear cross-phase modulation effect, the injected pulses referenced to an external clock serves as a stable and precise timing trigger for an effective intensity modulator. Read More

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Ultrafast laser ablation of a multicore polymer optical fiber for multipoint light emission.

Opt Express 2021 Jun;29(13):20765-20775

We demonstrate the use of ultrafast laser pulses to precisely ablate the side of polymer multicore optical fibres (MCF) in such a way that light is efficiently coupled out of a set of MCF cores to free space. By individually exciting sets of MCF cores, this flexible "micro-window" technology allows the controllable generation of light sources at multiple independently selectable locations along the MCF. We found that the maximum fraction of light that could be side coupled from the MCF varied between 55% and 73%. Read More

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SRS suppression in multi-kW fiber lasers with a multiplexed CTFBG.

Opt Express 2021 Jun;29(13):20535-20544

In this paper, we present experimental studies on newly developed multiplexed chirped tilted fiber Bragg gratings (MCTFBGs) for stimulated Raman scattering (SRS) suppression for high-power fiber laser systems. The MCTFBG device is composed of five continuous segments of chirped tilted fiber Bragg gratings (CTFBGs), which are inscribed into the large-mode-area (LMA, 25/400μm) fibers. The SRS suppression capability of the MCTFBG device has been successfully demonstrated with a master oscillator power amplification (MOPA) fiber laser system at the output level of 3. Read More

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Photonic device combined optical microfiber coupler with saturable-absorption materials and its application in mode-locked fiber laser.

Opt Express 2021 Jun;29(13):20526-20534

We demonstrated a mode-locked fiber laser based on a novel photonic device that combined optical microfiber coupler (OMC) and saturable absorption materials. The stable ultrafast laser was formed based on the interaction between the deposited Indium Antimonide (InSb) and the evanescent field on OMC. Different from optical microfiber (OM), OMC can directly output the mode-locked laser without additional beam splitting devices, which further improves the integrated characteristics of the fiber laser. Read More

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Single- and dual-wavelength fiber laser with multi-transverse modes.

Opt Express 2021 Jun;29(13):20299-20306

A single- and dual-wavelength fiber laser with multi-transverse modes is proposed. Mode interference is realized in the core of an optical fiber by writing a long period fiber grating on a few-mode fiber to obtain the LP mode and the LP mode simultaneously. A mode interferometer based on a few-mode long period fiber grating (FM-LPFG) is used as a comb filter in the ring-cavity fiber laser. Read More

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Supercontinuum generation in a carbon disulfide core microstructured optical fiber.

Opt Express 2021 Jun;29(13):19891-19902

We demonstrate supercontinuum generation in a liquid-core microstructured optical fiber using carbon disulfide as the core material. The fiber provides a specific dispersion landscape with a zero-dispersion wavelength approaching the telecommunication domain where the corresponding capillary-type counterpart shows unsuitable dispersion properties for soliton fission. The experiments were conducted using two pump lasers with different pulse duration (30 fs and 90 fs) giving rise to different non-instantaneous contributions of carbon disulfide in each case. Read More

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740-watt level optical tap coupler using side-polished large-mode-area double clad fibers for a high power fiber laser.

Opt Express 2021 Jun;29(13):19525-19530

We fabricated a fiber-optic directional coupler based on evanescent field coupling between side-polished large mode area (LMA) double clad fibers (DCFs) for a high power fiber laser. The tapping ratio of the fabricated coupler was measured to be - 32 dB. The fundamental mode coupled in a core of the lower side-polished fiber (SPF) was transferred to the upper SPF without clad-mode coupling. Read More

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Over 400 W graded-index fiber Raman laser with brightness enhancement.

Opt Express 2021 Jun;29(13):19441-19449

The power scaling on all-fiberized Raman fiber oscillator with brightness enhancement (BE) based on multimode graded-index (GRIN) fiber is demonstrated. Thanks to beam cleanup of GRIN fiber itself and single-mode selection properties of the fiber Bragg gratings inscribed in the center of GRIN fiber, the efficient BE is realized. For the laser cavity with single OC FBG, continuous-wave power of 334 W with an M value of 2. Read More

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Large-mode-area multicore Yb-doped fiber for an efficient high power 976 nm laser.

Opt Express 2021 Jul;29(14):21992-22000

We present an efficient 976 nm laser generation from an ytterbium (Yb)-doped step-index multicore fiber (MCF) with six cores placed in a ring shape. Each of the six cores has a large-mode-area (LMA) and a low numerical aperture (NA), which makes the MCF equipped with the features of a large core-to-cladding area ratio and differential bending loss for wavelength and mode selection. Hence, the Yb-doped MCF benefits 976 nm laser generation by simultaneously suppressing unwanted 1030 nm emission and higher-order modes (HOMs). Read More

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Investigation into the impact of the recovery time of a saturable absorber for stable dissipative soliton generation in Yb-doped fiber lasers.

Opt Express 2021 Jul;29(14):21978-21991

In this study, we conduct a numerical evaluation of the impact of the recovery time of a saturable absorber (SA) on the output performance of an Yb-doped fiber laser operating in the dissipative soliton regime. Particularly, we evaluate the output pulse characteristics, such as the pulse width, spectral bandwidth, pulse peak power, and pulse energy depending on the change in recovery time. Applying a too-slow SA recovery time above a certain critical value is shown to make the output pulse unstable and broken. Read More

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Efficient white upconversion luminescence in Yb/Eu doubly-doped transparent glass ceramic.

Opt Express 2021 Jul;29(14):21763-21772

Efficient white upconversion (UC) luminescence is obtained in Yb/Eu doubly-doped optical glass ceramic (GC) for the first time. KYbF nanocrystals are controllably precipitated from the amorphous networks via the inducing of Yb. Yb ions are spontaneously confined within the compact fluoride crystal structures to produce efficient blue UC emissions of Yb-Yb pairs. Read More

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Tunable narrowband cascaded random Raman fiber laser.

Opt Express 2021 Jul;29(14):21539-21550

Random Raman fiber lasers (RRFLs) with half-opened cavity have been used as a new platform for designing high performance, wavelength-agile laser sources in the infrared region due to their intrinsic modeless property and structural simplicity. To provide the point feedbacks for cascaded random Raman lasing at different wavelengths, wavelength-insensitive broadband reflectors are commonly used in cascaded RRFLs, resulting in the rather broad high-order random Raman lasing with several nanometers of typical spectral width. Here, we experimentally demonstrate a tunable narrowband cascaded RRFL with an air-spaced etalon assisted point reflector. Read More

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Tailoring the efficiency and spectrum of a green random laser generated by frequency doubling of random fiber lasers.

Opt Express 2021 Jul;29(14):21521-21529

Frequency doubling of random fiber lasers could provide an effective way to realize visible random lasing with the spectrum filled with random frequencies. In this paper, we make a comprehensive study on the efficiency and spectral manipulation of a green random laser generated by frequency doubling of an ytterbium-doped random fiber laser (YRFL). To tailor the efficiency of green random lasing generation, the ytterbium-doped random fiber lasing is filtered at different spectral positions, and then amplified to watt-level to serve as the fundamental laser source for frequency doubling in a periodically poled lithium niobate (PPLN) crystal. Read More

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Single-frequency 1.7-μm Tm-doped fiber laser with optical bistability of both power and longitudinal mode behavior.

Opt Express 2021 Jul;29(14):21409-21417

The single-frequency operation of a thulium fiber laser at a short wavelength of 1720 nm is investigated in a ring resonator. Powerful single-longitudinal-mode operation was realized by utilizing an unpumped thulium-doped fiber as the saturable absorber. The fiber laser delivered 407 mW single-frequency output with a spectral linewidth of 4. Read More

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Time-encoded stimulated Raman scattering microscopy of tumorous human pharynx tissue in the fingerprint region from 1500-1800  cm.

Opt Lett 2021 Jul;46(14):3456-3459

Stimulated Raman scattering (SRS) microscopy for biomedical analysis can provide a molecular localization map to infer pathological tissue changes. Compared to spontaneous Raman, SRS achieves much faster imaging speeds at reduced spectral coverage. By targeting spectral features in the information dense fingerprint region, SRS allows fast and reliable imaging. Read More

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Kilowatt level Raman amplifier based on 100  µm core diameter multimode GRIN fiber with M = 1.6.

Opt Lett 2021 Jul;46(14):3432-3435

In this Letter, we demonstrate a high-power Raman fiber amplifier with excellent beam quality based on graded-index fiber. The Yb-doped fiber laser (YDFL) and bandwidth-tunable amplified spontaneous emission (ASE) source are employed as the pump source to compare the laser performance separately. When the ASE with a bandwidth of 8 nm is employed, a maximum power of 943 W at 1130 nm is achieved, which is twice that pumped by YDFL. Read More

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Avoidance of four-wave mixing in optical fiber bundle for coherent anti-Stokes Raman scattering endomicroscopy.

Opt Lett 2021 Jul;46(14):3356-3359

We propose and demonstrate a method of suppressing four-wave mixing (FWM) in an optical fiber bundle to realize coherent anti-Stokes Raman scattering (CARS) endomicroscopy, which is the leading candidate for a definitive diagnosis of gastrointestinal cancer. Two excitation laser beams with different wavelengths are delivered via different cores to suppress FWM and are then combined with a polarization prism and a dual-wavelength wave plate and are focused to a spot. The background emission from the optical fiber bundle was suppressed to 1/3289, and we demonstrated CARS imaging of a polystyrene bead using the proposed method. Read More

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Mode converter with C+L band coverage based on the femtosecond laser inscribed long period fiber grating.

Opt Lett 2021 Jul;46(14):3340-3343

The mode converter (MC) is one of the key components for mode division multiplexing (MDM). Here, we experimentally demonstrate an all-fiber long period grating (LPG) based MC inscribed in the few-mode fiber (FMF) with the line-by-line femtosecond laser irradiation technique. Experimental characterization results agree well with the theoretical calculations, and a clear mode evolution from the mode to the mode is observed with the tuning of the operation wavelength. Read More

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Self-starting triple-wavelength vector dark soliton with a bismuth-doped fiber saturable absorber.

Opt Lett 2021 Jul;46(14):3336-3339

We report on the generation of a triple-wavelength vector dark soliton in an all-fiber ring cavity of erbium-doped fiber laser mode-locked with a bismuth-doped fiber saturable absorber. The formation of the triple-wavelength vector dark soliton is due to the cross-phase coupling derived from the cavity birefringence. The mode-locked laser operated at a 1. Read More

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Relaxation characteristics for efficient fluorescence lifetime detection of gain media in the fiber laser.

Appl Opt 2021 Jul;60(19):5678-5681

By using different active materials as gain media, we demonstrate a system aimed to measure the fluorescence lifetime of gain media in the fiber laser by utilizing the correlation between the laser's relaxation oscillation characteristics and the fluorescence lifetime of the active materials. As the advantages of extremely compact configuration, non-destructive and real time of the system, the fluorescence lifetime of gain media composed of materials of erbium-ytterbium-doped or erbium-doped have been measured, whose results are 20.2 µs and 1. Read More

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