Nd:KGW Laser under Flashlamp-pumping at Repetition Rate up to 50 Hz and Average Power of 70 W (free-lasing and Q-switched mode)

The laser performance of Nd:KGd(WO4)2 crystal or Nd:KGW has been studied under flashlamp-pumping in the free-running and Q-switched mode (with active or passive Q-switching) at repetition rate up to 50 Hz. Maximum output powers respectively of 70 and 30 W were achieved at 1.06 pm with a maximum efficiency of 6%. Free-running emission was also obtained at 1.35 pm with a maximum average power of 24 W and a total efficiency of 2.9% at this wavelength. A comparison with a similar Nd:YAG crystal is given showing a noticeable advantage for Nd:KGW.

Flashlamp-pumped Nd:KGW laser at repetition rates up to 50 Hz

:YAG passive element. Energies up to 1.1 J and 550 mJ, respectively, are obtained with a total efficiency close to 3%.

CW and Q-switched diode end-pumped Nd:YAP laser at 1.34 µm. Influence of Nd doping level

A multi watt CW 1.34 µm diode end-pumped Nd:YAP laser is described. Acoustooptic device is tested to obtain Q-switched operation. The influence of the Nd3+ doping level in YAP crystal on the laser efficiency, in CW and in Q-switched mode, is presented.

Testing a portable laser-induced breakdown spectroscopy system on geological samples.

9 pages; International audience; This paper illustrates the potentialities of a home-made portable LIBS (laser-induced breakdown spectroscopy) instrument in Earth sciences, more particularly in geochemically recognizing (i) tephra layers in lacustrine sediments and (ii) fossilization processes in ammonites. Abundances for selected lines of Al, Ca, Fe, Ti, Ba and Na were determined in lacustrine chalk sediments of the Jura, where the Laacher See Tephra (LST) layer is recorded. A statistical treatment of elemental maps produced from the section of a sedimentary column containing the LST event allows instrumental conditions to be optimized. Accumulating spectra from close shot positions gives …

Comparative laser study of Nd:KGW and Nd:YAG near 1.3 μm

A comparative study of Nd:KGW and Nd:YAG laser crystals pumped by flashlamp has been conducted near 1.3 μm with output energy up to 1 J and at a repetition rate up to 50 Hz. An average power of 23 W for KGW in free-running mode was achieved with a total efficiency better than 2.8 % for the Nd:KGW and 1.8 % for the Nd:YAG.

On the potential of 914 nm pumping of Nd:YVO4 for laser operation at 1064 nm

1064 nm-Nd :YVO4 lasers were pumped at 808 nm and 914 nm. The comparative study shows that 914 nm-pumping is adapted for cw operation whereas 808 nm-pumping provides higher population inversion interesting for Q-switched operation.

50 mJ/30 ns FTIR Q-switched diode-pumped Er:Yb:glass 1.54 μm laser

Abstract 50 mJ Q-switched output at 30 ns pulse duration was demonstrated with a transversely diode-pumped bulk Er 3+ :Yb 3+ :glass 1.54 μm laser system of uncomplicated and compact design, using a piezoelectrically driven FTIR shutter. In long-pulse operation, 360 mJ output was obtained for 2.65 J incident optical pump energy. Maximum optical slope efficiencies of 20.5% and 5.4% were measured in long-pulse and Q-switched operation, respectively. Optimum Q-switch timing was studied taking into account the Yb 3+ →Er 3+ energy transfer process and was correlated with free-running delay parameters.

Diode-pumped bulk Er:Yb:Glass 1.54μm pulsed laser with 1.2J output and 25% optical efficiency

We report a pulsed transversely diode-pumped compact Er:Yb:Glass laser of uncomplicated design, delivering output energy of approx. 1.2J in free-running operation and 25% optical slope efficiency.

Characteristics of laser operation at 1064 nm in Nd:YVO_4 under diode pumping at 808 and 914 nm

International audience; A comparative study between 808 and 914nm pumping of Nd:YVO4 crystals for laser operation at 1064nm has been carried out. Using similar setups, performances of both configurations were first studied in the continuous wave, small-signal gain, and Q-switched regimes. Thanks to a numerical model, it is shown that fluorescence quenching and upconversion processes limit the possible uses for the 914nm pumping scheme to regimes with low population inversions

A review of the development of portable laser induced breakdown spectroscopy and its applications

Abstract In this review, we present person-transportable laser induced breakdown spectroscopy (LIBS) devices that have previously been developed and reported in the literature as well as their applications. They are compared with X-ray fluorescent (XRF) devices, which represent their strongest competition. Although LIBS devices have advantages over XRF devices, such as sensitivity to the light elements, high spatial resolution and the possibility to distinguish between different layers of the sample, there are also disadvantages and both are discussed here. Furthermore, the essential portable LIBS instrumentation (laser, spectrograph and detector) is presented, and published results related…

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

Flashlamp-pumped Ti:Sapphire laser: Influence of the rod figure of merit and Ti3+ concentration

A flashlamp-pumped Ti:Sapphire laser is tested with rods of various Figures of Merit (FOM from 100 to 800) and Ti3+ concentrations (0.1 and 0.15% by weight) and we measured the laser energy dependence as a function of these parameters. Output energies above 2 J are obtained without dye converter, leading to a 1.8% overall efficiency and a 2.2% slope efficiency. The effects of pump pulse duration by variation of the discharge capacitance are also monitored.

Phase-conjugate emission of a two-mirror solid state laser

We show that phase conjugation strongly contributes to the emission of a solid state laser in a two-mirror (Fabry-Perot) resonator , enabling dynamic correction of thermal lensing . Full correction of thermal effects is reached by vector phase conjugation .

Efficient pulsed 946-nm laser emission from Nd:YAG pumped by a titanium-doped sapphire laser

Efficient pulsed room-temperature laser emission at 946 nm is obtained from a Nd:YAG rod pumped by a Ti-doped sapphire laser in the free-running mode. Three bonded YAG rods of 3-mm diameter with different Nd concentrations and active lengths were tested. A maximum output energy of 83.5 mJ at 3 Hz was obtained with a slope efficiency of 32.3% in an end-pumping configuration.

A compact and portable laser-induced breakdown spectroscopy instrument for single and double pulse applications

Abstract We present LIBS experimental results that demonstrate the use of a newly developed, compact, versatile pulsed laser source in material analysis related to art and archaeological applications in view of research aiming at the development of portable LIBS instrumentation. LIBS qualitative analysis measurements were performed on various samples and objects, and the spectra were recorded in gated and non-gated modes. The latter is important because of advantages arising from size and cost reduction when using simple, compact spectrograph-CCD detection systems over the standard ICCD-based configurations. The new laser source exhibited a very reliable performance in terms of laser pulse …

In situ Laser Induced Breakdown Spectroscopy as a tool to discriminate volcanic rocks and magmatic series, Iceland.

7 pages; International audience; This study evaluates the potentialities of a lab-made pLIBS (portable Laser-Induced Breakdown Spectroscopy) to sort volcanic rocks belonging to various magmatic series. An in-situ chemical analysis of 19 atomic lines, including Al, Ba, Ca, Cr, Cu, Fe, Mg, Mn, Na, Si, Sr and Ti, from 21 sampled rocks was performed during a field exploration in Iceland. Iceland was chosen both for the various typologies of volcanic rocks and the rugged conditions in the field in order to test the sturdiness of the pLIPS. Elemental compositions were also measured using laboratory ICP-AES measurements on the same samples. Based on these latter results, which can be used to ident…

Pulse timing effects in bulk Er/Yb codoped diode-pumped eyesafe lasers

In this work, diode-pumping with appropriately modulated pulses is used to expose subtle input / output pulse-timing characteristics of Er3+ /Yb3+ systems, study their relation to laser efficiency and demonstrate some unique laser-pulse timing behavior. Er+3/Yb+3 codoped glass and YAG laser-host materials with similar concentrations (optimized for eyesafe emission in the 1.6-mum region) were studied in the same diode-pumped setup, in similar resonator configurations and analogous operating conditions.

In situ carbon and oxygen isotopes measurements in carbonates by fiber coupled laser diode-induced calcination: A step towards field isotopic characterization

International audience; Natural stable isotopes ratios (δ13Ccarb and δ18Ocarb) of carbonates archived in the geological record are routinely used to reconstruct local and global paleo temperatures and the secular evolution of the biogeochemical carbon cycle. The state-of-the-art technique, employed since the mid 20th century, to measure these isotopic ratios starts with field sampling followed by several steps of physical and chemical laboratory preparation including: (i) microdrilling and/or sawing and crushing, (ii) CO2 release by wet acid digestion, (iii) gas equilibration, purification and transfer, before (iv) gas phase IRMS measurements. While these steps are time and resource consumi…

Flashlamp-pumped Nd:KGW laser in MOPA configuration: comparative study of several rods

The laser performance of the Nd:KGW crystal has been studied in a master oscillator and power amplifier configuration (MOPA). Several crystals from two different producers were investigated for the oscillator and the amplifier. A maximum single-pass gain of 25 was observed in free-running and Q-switched mode. We obtained a maximum output amplified energy of 400 mJ at 30 Hz (with a pulse duration of 10 to 30 ns) with a divergence less than 3 mrad. We also studied the limitations of this configuration due to the very high gain of the Nd:KGW crystal.

Towards calibration transfer for quantitative analysis of nuclear materials by LIBS

To ensure the quality of their products, manufacturers of nuclear materials currently rely on wet chemistry methods coupled with ICP-MS and ICP-AES. These methods are slow and sometimes hard to implement, which leads the manufacturers to seek new possibilities of online, fast and direct preliminary quality control. Thus, the issue of quantifying metal impurities in both uranium and plutonium matrices by LIBS has been raised. But the lack of calibrated samples and the harsh security constraints hinder any possibility of complete analytical development on these materials. Therefore, we propose a method relying on calibration transfer from several non-nuclear metal matrices to uranium and plut…

1.65-μm Er:Yb:YAG diode-pumped laser delivering 80-mJ pulse energy

We demonstrate efficient lasing of bulk diode-pumped Er 31 :Yb 31 :YAG at 1.645 mm. The material is transversely pumped using three quasi-cw 960-nm laser diode arrays in a simple arrangement. In the free-running mode of operation, an output pulse energy of 79 mJ is obtained at 4.7 J of incident optical pump energy. The lasing threshold lies in the range 1.0 to 1.9 J in long-pulse operation, depending on pumping conditions, and optical slope efficiencies of 2.2% to 3.4% were measured with respect to the incident pump energy. Furthermore, initial Q-switching experiments with a Co:MALO saturable absorber yielded pulses of 1.7-mJ energy and 340-ns FWHM duration. As the reported laser setup also…

Characterization of laser ablation of copper in the irradiance regime of laser-induced breakdown spectroscopy analysis

Abstract The LIBS signal depends both on the ablated mass and on the plasma excitation temperature. These fundamental parameters depend in a complex manner on laser ablation and on laser–plasma coupling. As several works in the literature suggest that laser ablation processes play a predominant role compared to plasma heating phenomena in the LIBS signal variations, this paper focuses on the study of laser ablation. The objective was to determine an interaction regime enabling to maximally control the laser ablation. Nanosecond laser ablation of copper at 266 nm was characterized by scanning electron microscopy and optical profilometry analysis, in air at 1 bar and in the vacuum. The laser …

Comparison between 2 Different Composite Nd3+:YVO4 Crystals in a Fibre Coupled Diode Pumped Laser

International audience; We detail the performances of two composite Nd3+YVO4crystals, realised with two different sticking techniques. We tested them inside a fibre coupled diode end pumped laser.