Search results for "laser"

Actively mode-locked all-fiber laser by 5 MHz transmittance modulation of an acousto-optic tunable bandpass filter

2018

Active mode-locking of an all-fiber ring laser by transmittance modulation of an in-fiber acousto-optic tunable bandpass filter (AOTBF) is reported. Cavity loss modulation is achieved by full acousto-optic mode re-coupling cycle induced by standing flexural acoustic waves. The modulator permits the implementation of 28 dB of nonresonant light suppression, 1.4 nm of modulation bandwidth, 74% of modulation depth and 4.11 dB of optical loss in a 72.5 cm-long all-fiber configuration. The effects of the modulated AOTBF on the laser performance are investigated. Transform-limited optical pulses of 8.8 ps temporal width and 6.0 W peak power were obtained at 4.87 MHz repetition rate.

Time-domain fiber laser hydrogen sensor.

2004

We report a novel scheme for a fiber-optic hydrogen sensor based on an erbium-doped fiber laser with a palladium-coated tapered fiber within the laser cavity. The tapered fiber acts as a hydrogen-sensing element. When the sensing element is exposed to a hydrogen atmosphere, its attenuation decreases, changing the cavity losses and leading to a modification of the laser transient. The hydrogen concentration is obtained by simple measurement of the buildup time of the laser. This technique translates the measurement of hydrogen concentration into the time domain, and it can be extended to many intensity-based fiber sensors. Relative variations in the buildup time of up to 55% at an increase o…

Formation of Femtosecond Parabolic Pulses in Normal-Dispersion Optical Fibers

2013

We have shown through extensive numerical simulations that application of passive nonlinear reshaping in normal-dispersion optical fibers could produce femtosecond parabolic pulses (a few hundreds fs) modern femtosecond lasers and commercially available fibers.

Shaping the supercontinuum spectral profile

2009

We numerically recognize a procedure for shaping, at least to some extent, the spectral profile of the supercontinuum (SC) generated by soft-glass photonic crystal fibers (PCFs). As example, we identify a PCF geometry that provides an ultrawide (over an octave) and very flat SC when pumped with pulsed light parameters corresponding to a commercially available Er-doped femtosecond fiber laser.

Intensity-Modulated Optical Fiber Sensor for AC Magnetic Field Detection

2015

An erbium-doped (Er3+) fiber optic laser is proposed for sensing alternated magnetic fields by measuring the laser intensity modulation. The sensor is fabricated using two partially overlapped narrow-band fiber Bragg gratings (FBGs) and a section of doped fiber in a Fabry–Perot configuration. Laser power stability and bandwidth are studied while changing the overlap. A bulk rod of TbDyFe, a magnetostrictive material, is glued to both the FBGs and the laser wavelength and power are modulated according to the magnetic field. Acquisition and processing are done using virtual instrumentation. Results have shown the possibility of detecting 11.18 $\mu \text{T}_{\mathrm {{rms}}}/\surd $ Hz for an…

Conical Fiber Probe for Mechanical Stabilization of Microbubbles in Liquids

2020

We demonstrate that a cone pierced in a fiber tip can stabilize microbubles photothermally generated in liquids. Bubbles can stand and monitor pressure shocks over 3.3 bar with a sensitivity below 7 mbar.

Erratum: “Enhanced acoustic pressure sensors based on coherent perfect absorber-laser effect” [J. Appl. Phys. 129, 104902 (2021)]

2021

Flashlamp-Pumped Nd:KGW Laser at 1.06 and 1.35 μm in Free-Running and Q-Switched Mode Results in MOPA Configuration

2005

Sample building orientation effect on porosity and mechanical properties in Selective Laser Melting of Ti6Al4V titanium alloy

2022

Abstract In recent decades, the focus of research has shifted towards new production technologies with the aim of optimizing production and reducing costs. These innovative technologies include additive manufacturing processes as Selective Laser Melting (SLM). The analysis of the literature on the identification of optimal building orientation to maximize the mechanical properties and minimize porosity of the final products highlights contrasting results, denoting that the thermomechanical complexity of the process, as associated with the variation of the building orientation, has not been fully clarified. A study in which the building orientation effect was evaluated together with the geom…

Laser heating and ablation at high repetition rate in thermal confinement regime

2006

International audience; Laser heating and ablation of materials with low absorption and thermal conductivity (paint and cement) were under experimental and theoretical investigations. The experiments were made with a high repetition rate Q-switched Nd:YAG laser (10 kHz, 90 ns pulse duration and l = 532 nm). High repetition rate laser heating resulted in pulse per pulse heat accumulation. A theoretical model of laser heating was developed and demonstrated a good agreement between the experimental temperatures measured with the infrared pyrometer and the calculated ones. With the fixed wavelength and laser pulse duration, the ablation threshold fluence of paint was found to depend on the repe…