Abstract In this work, an all-fiberized and narrow-linewidth fiber amplifier with record output power near-diffraction-limited beam quality is presented. Up to 6.12 kW laser the conversion efficiency of approximately 78.8% achieved through based on a conventional step-index active fiber. At maximum power, 3 dB spectral linewidth 0.86 nm factor M x 2 = 1.43, y 1.36. We have also measured compared properties employing different pumping schemes. Notably, practical limit could be estimated...

Abstract The high-power narrow-linewidth fiber laser has become the most widely used source nowadays. Further breakthroughs of output power depend on comprehensive optimization stimulated Brillouin scattering (SBS), Raman (SRS) and transverse mode instability (TMI). In this work, we aim to further surpass record all-fiberized amplifiers with near-diffraction-limited (NDL) beam quality. SBS is suppressed by white-noise-signal modulation a single-frequency seed. particular, refractive index...

The development of tumor-associated, stimuli-driven, turn-on near-infrared (NIR) fluorophores requires urgent attention because their potential in selective and precise tumor diagnosis. Herein, we describe a NIR fluorescent probe (CyA-cRGD) comprised fluorescence reporting unit (a cyanine dye) linked with GSH-responsive (nitroazo aryl ether group) tumor-targeting (cRGD). CyA-cRGD sensitive response to GSH can act as direct off–on signal reporter for monitoring. Notably, possesses improved...

We systematically investigated the dependence of mode instability (MI) thresholds on bending diameters in ytterbium-doped fiber amplifiers. The MI a amplifier, which was based multimode fiber, were measured at various diameters. It is found that correlation between and depends operation state active fiber. When few-mode operation, threshold successfully raised from 717 W to 1084 by increasing diameter 11 cm 60 cm. operates quasi-single mode, 953 reducing 8 According our experiments previous...

The radical suppression of the photodarkening effect and laser performance deterioration via <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" id="m1"> <mml:mrow> <mml:msub> <mml:mi mathvariant="normal">H</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:math> loading were demonstrated in high-power Yb-doped fiber (YDF) amplifiers. loss at equilibrium was 114.4 dB/m 702 nm pristine fiber, while it vanished id="m2"> -loaded fiber. To obtain a deeper...

In this paper, we realize a 3.96 kW all-fiberized and polarization-maintained (PM) amplifier with narrow linewidth near-diffraction-limited beam quality. Based on master oscillator power (MOPA) configuration seeded phase-modulated single-frequency laser, signal laser is achieved 3 dB of 0.62 nm at the pump 5.02 kW. At maximum output power, polarization extinction ratio (PER) ~13.9 dB, quality (M2 factor) M2x = 1.31, M2y 1.41. As far as know, PM fiber all-fiber format.

A confined-doped fiber was fabricated by a modified chemical vapor deposition (MCVD) process based on refractive index matching technology. With theory and experiments, we compared the normal-doped fiber. We found that with core of 35 μm 0.07 numerical aperture could achieve single-mode output improve beam quality from 2.8 to 1.5 in laser. Meanwhile, it still possesses high laser efficiency has good stability increase pump power. It suggests MCVD may be key material for high-power excellent quality.

Photothermal therapy (PTT) was considered as one of the most promising cancer therapies to overcome severe side effects caused by chemotherapy. To develope four thiophene analogs construct novel organic photothermal agents (PTAs) for many biomedical applications in biosensing and therapies. The efficacy compounds demonstrated studies properties well therapeutic effects. Tumor ablation experiments indicated that HTN2 can effectively suppress tumors vivo vitro a PTA. PTAs we designed...

In this work, we quantitatively investigate the SBS threshold in high-power narrow-linewidth fiber amplifiers seeded with phase-modulated single-frequency lasers presence of weak end feedback. The impacts feedback and spectral linewidths on are demonstrated detail through comparative experiments numerical simulations, respectively. experiment, have pointed out a practical method to estimate reflectivity amplifiers. Based estimation, characters different seed investigated. By reducing...

Development of photothermal agents for imaging-guided therapy (PTT) has been great interest in the field nanomedicine.

A homemade 25/400 thulium-doped silica fiber for high power laser and an all-fiber bi-direction pumped master-oscillator power-amplifier (MOPA) configuration with output of 406 W are presented. The concentration Tm <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Al was set as 2.6 wt.% 1.01 respectively. Cladding Absorption at 793 nm measured to be 3 dB/m. obtained by improving coating...

A novel method for mitigating photo-darkening and the effective photo-bleaching phenomenon by 532 nm cladding pump in Yb-doped fiber were herein reported. Compared with pristine fiber, beyond 30% of induced excess loss was suppressed pretreatment. Moreover, photo-darkened completely bleached pump. Additionally, exhibited better resistance. Therefore, high power application, a 20/400 gamma irradiated situ laser properties explored. The output restored to 421W accounting 82% mode instability...

In this work, the influence of four-wave mixing (FWM) effects on transverse mode instability (TMI) is incorporated into TMI model based stimulated thermal Rayleigh scattering. The capable analyzing gain characteristics different high-power fiber amplifiers, which physical mechanism and functioning boundary FWM are theoretically investigated. Consequently, a new threshold formula defined to resolve inconsistencies in previous models. It revealed that it extremely necessary consider...

A superfluorescent fiber source (SFS) is a special that commonly possesses high temporal stability and wide spectral linewidth. In this work, an all-fiberized linearly polarized SFS with, to our knowledge, record output power near-diffraction-limited beam quality presented. Up 5.03 kW achieved at pump of 6.18 with corresponding conversion efficiency ∼81.1%. At maximum power, the signal-to-noise ratio background noise over 50 dB, polarization extinction ∼17dB, factor Mx2=1.49, My2=1.44....

A simplified model based on the finite-element method is proposed to study thermo-optic behavior in high-power fiber amplifiers. It shown that thermally induced refractive index change results a thermal lens effect and ultimately leads multimode even an intrinsically single-mode fiber. Besides, experimental investigations were carried out characterize of large mode area 20/400 ytterbium-doped with core numerical aperture (NA) ~ 0.04 all-fiber amplifier. Output power up 1.68 kW was achieved...

Stimulated Raman scattering (SRS) and transverse mode instability (TMI) effects are crucial limitation factors for further power scaling of high-power fiber amplifiers with near-diffraction-limited beam quality. It is an important research direction to carry out laser system optimization from the perspective seed construction. In this work, we experimentally investigated impact utilizing different lasers on SRS TMI characteristics in high ytterbium-doped amplifiers. Both phase modulated...

<bold>DMP</bold>exhibits high tumor cell affinity and favorable mitochondria-targeting capability.<bold>DMP</bold>exhibits pH stability good water-solubility.

The laser efficiency and temperature distribution in distributed side-coupled cladding-pumped (DSCCP) fiber lasers are investigated, using a precise complete analytic model. We show that high-order mode pump handling (N + 1) ≥ 2) DSCCP fibers can achieve high when the separated. In terms of multistage schemes, requires an appropriate pump-node number arrangement. According to our calculations, evolution along signal could give rise fluctuation case strong coupling, which decrease instability...

We report on the photobleaching effect photodarkening in an ytterbium (Yb)-doped silica double-cladding fiber by pumping it with 793 nm, 808 nm and 1080 lasers. Enlightened different recovery processes under 808nm pumps, is suggested that thulium (Tm) plays important roles of a Yb-doped fiber. Based related reports, new idea proposed, stating bleaching phenomena could be analyzed from concept e− h+ equilibrium. The due to electron, ionized ultraviolet photon. offset h+. Tm ions, existing as...

Ytterbium-doped fiber (YDF) loaded with deuterium is used herein to mitigate mode instability. Experimental results reveal that this method can increase the instability threshold in a laser oscillator. Specifically, when YDF was over two- and four-week periods, power increased from ∼459 W ∼533 (16%) ∼622 (35%), respectively, but respective efficiencies were almost unaffected (71.5% vs. 72.9% 75.4%). In conclusion, loading effective mitigation of It envisaged be applied scaling high-power lasers.