Abstract A numerical model for amplification of ultrashort pulses with high repetition rates in fiber amplifiers is presented. The pulse propagation modeled by jointly solving the steady-state rate equations and generalized nonlinear Schrödinger equation, which allows accurate treatment dispersive effects whilst considering arbitrary spatial spectral gain dependencies. Comparison data acquired using developed experimental results prove to be good agreement.

Abstract In order to assess the geochemical retention properties of rocks, which will be final barrier for radionuclide transport biosphere in case a failed deep underground repository spent nuclear fuel, sorption experiments are usually made with crushed material. This raises issue extrapolating results obtained from laboratory field scale. As is generally related surface area geological material, it then important consider dependency specific on particle size. this work, BET determinations...

The velocity of longitudinal elastic waves is measured between room temperatures and 880 °C in polycrystalline iron compared with predictions several theoretical models utilizing single‐crystal constants from the literature. Wave velocities are successive reflected peaks laser‐ultrasonic signals very high precision accuracy. Iron chosen as test material because its inherent crystal anisotropy varies widely over this temperature range. Great care taken processing to ensure a suitable...

8 mm long channel waveguides were manufactured in polycrystalline diamond with inductively coupled plasma etching and characterized terms of mode-profile propagation loss the 1.5 – 3.4 μm spectral region. As proof principle, evaluated an evanescent field sensing setup targeting CH absorption peak isopropanol at ~3.4 μm, showing good agreement numerical finite element simulations.

This work demonstrates an actively mode-locked fiber laser operating in soliton regime and employing all-fiber electro-optic modulator. Nonlinear polarization rotation is utilized for femtosecond pulse generation. Stable operation of the ring readily achieved at a fundamental repetition rate 2.6 MHz produces 460 fs pulses with spectral bandwidth 5.3 nm.

Cavity dumping of an all-fiber laser system is demonstrated. The active element a pulse-picker with nanosecond rise time consisting microstructured fiber electrically driven internal electrodes. device used for intracavity polarization rotation and through splitter. optical flux removed from the cavity within one roundtrip most amplified spontaneous emission, spiking relaxation oscillation that follow during gain recovery phase are blocked output signal.

The paper summarizes the creation of a robust online grain size gauge for hot strip mill. A method and algorithm calculating from measured ultrasonic attenuation is presented. This new self-calibrating, does not rely on geometrical reference sample can cope with effects diffraction attenuation. model based 52 quenched samples more than 23,000 laser ultrasonics shots has correlation coefficient R2 0.8. Typical measurements mill calculated versus length are presented couple steel strips.

Various approaches are reviewed for determining elastic anisotropy and its coupling to crystallographic texture, with special reference ultrasonic measurements. Two new methods described measuring the of P-wave velocity using laser-ultrasonics. Making measurements across diameter a cylindrical specimen as it is rotated makes possible maintain very constant known path length. This permits extremely accurate precision better than 0.01%. Results on 316 stainless steel in different conditions...

Actively Q-switching of an all-fiber laser system is demonstrated. The active element a polarization switch with nanosecond risetime based on microstructured fiber electrically driven internal electrodes. Optical feedback between two 100% reflectors inhibited until current pulse Q-switches the laser. After short optical develops several roundtrips later, turned off, removing from cavity through splitter. Pulses 50 W peak power and approximately 12 ns duration are obtained 400 mW pump at 100 Hz.

In this paper, we give an overview of recent results on switching light in fibers with internal electrodes. Polarization rotation, nanosecond gating, and wavelength fiber Bragg gratings long period are discussed. Applications exemplified Q-switching lasers RF-signal filtering.

Eutrophication is a major threat to the Baltic Sea, causing algae blooms and hypoxic bottoms.Ecological engineering methods aiming at help mitigating nutrient imbalance problems have already been initiated or are being planned in coastal zones of Sea.This includes harvesting reed, macro blue mussels as energy natural resources.The potential feasibility such form basis for sustainable use resources governed by ecological, technical, economic social aspects associated with whole chain...

Two designs of diamond quarter-wave plates for CO2 lasers, based on the birefringence sub-wavelength gratings, were manufactured and tested. In one design grating was etched surface a 300 µm thick polycrystalline substrate. The other consisted hanging freely in air, suspended at edges from silicon frame. free-hanging design, while more fragile, had several advantages both terms fabrication performance such as larger period, higher transmission, no need an antireflective treatment backside.

Two 78-cm long electrooptic fibers with nonlinear coefficient χ((2)) ~0.26 pm/V are used in a Sagnac loop for pulse selection at up to 1 MHz repetition rate. Laser pulses of 1.5 µm wavelength arriving every 140 ns selected an extinction ratio as high -30 dB. The arrangement is entirely based on silica fiber.

Abstract In general sorption coefficients, K d , cat ion exchange capacity, CEC, and BET surface areas are measured on crushed rock samples because it is very time consuming to measure CEC larger pieces as takes a long for the sorbing species penetrate into equilibrate large sample. Also conventional sample holders measurements too small hold We have manufactured modified equipment so that possible with 50 mm diameter up 100 length. Results presented intact compared results material from...

In this study, we demonstrate the significance of austenite annealing twin boundaries when calibrating laser ultrasonic measurements for gauging grain size in situ during thermomechanical processing high-strength low-alloy steels. Simple calculations show how differences twinning density can lead to errors if twins are disregarded calibration and method is used a broad range Conversely, performed using alloys with metastable microstructure at room temperature, same suitable HSLA steels,...

The performance of a 6.5 GHz hybrid GaN Doherty power amplifier is reported. packaged in plastic overmold QFN 9×9 package and includes discrete transistors integrated passive GaAs splitting, matching combiner networks. Measured results, under continuous wave operation, at shows 18 dB gain, P1dB 42 dBm, 21% PAE 9 output back off. These results are the first reported for that comes close to specifications typical point-to-point microwave link application. Furthermore, presented approach step...

We demonstrate the addition of time gating to a standard optical spectrum analyzer (OSA) operating in spectral region ~1.06μm . This is accomplished by opening for 7 ns input OSA with an electrically driven poled fiber Sagnac loop. The sequential interrogation nanosecond resolution reflection from three Bragg gratings along piece allows distinguishing peaks created minimum separation 85 cm. passive extinction ratio this device >40 dB and returns >23 on 35-ns scale directly after gating.