Emission and excitation spectra of Er-doped YAP crystals reveal a broad emission band in the eyesafe region with peaks
around 1545-nm and 1608-nm and pump-bands suitable for common 800-nm and 970-nm diode lasers, suggesting YAP
as a candidate crystalline host for diode-pumped laser in the 1.5-μm eyesafe regime. Erbium-doped YAP-crystal results
are comparable with analogous measurements on Er:Yb:YAG, which has already demostrated efficient lasing action in
the eyesafe region.
The initiation of pyrotechnic substances by a laser light has been studied for more than 30 years. But
until recently the use of this technology for defence applications encountered three main technical
problems: the volume and the mass of lasers, the linear loss of optical fibres and their possible
damage caused by the transport of strong laser power. Recent technical progress performed in the
field of electrical and optical devices are now very promising for future opto-pyrotechnic functional
chains.
The objective of this paper is to present a demonstrator developed in order to initiate in a
synchronous way four optical detonators and to measure the dispersion of their functioning times. It
includes four compact Q-switched Nd:Cr:GSGG solid laser sources, pumped by flash lamp (energy
≈110mJ, FWHM ≈8.5 ns), two ultra-fast electro-optical selectors (based on RTP crystals) used to
steer the laser beam and six optical fibre lines to transmit the laser pulses to the optical detonators.
The set-up integrates also complex control and safety systems, as well as cameras allowing an
optimal alignment of optical fibres.
Experiments led us to initiate in a synchronous way four detonators with a mean scattering of 50 ns.
The perspectives in this domain of initiation concern mainly the miniaturization and the hardening to
the environments of electrical and optical components.
Diode-pumping with appropriately modulated pulses is used to expose subtle input / output pulse-timing characteristics
of Er3+:Yb3+-codoped systems, particularly Er3+:Yb3+:glass and Er3+:Yb3+:YAG, and study their relation to laser
efficiency. In free-running operation, these systems may persist to lase for uncommonly long time periods (up to a ms)
after the pump stops. In Q-switched operation, maximum laser output is obtained only if Q-switching is purposely
delayed for some significant additional time (typically 50-500μs) following the end of the pump pulse. Furthermore,
pump-pulse duration affects profoundly the Er3+:Yb3+-laser output performance, especially in Q-switched mode.
Numerical modeling simulations are presented, accounting for the observed effects and extrapolating them to novel
regimes of Er3+:Yb3+-laser operation.
We present LIBS experimental results that demonstrate the use of a newly compact, versatile pulsed laser source in
material analysis in view of research aiming at the development of portable LIBS instrumentation. LIBS qualitative
analyses were performed on various samples and objects, and 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 Nd3+:YAG laser source exhibited very
reliable performance in terms of laser pulse repeatability, autonomy and interface. Indeed, it can deliver a 45 mJ for 4.5 ns
pulse and work at 1 Hz. Having the ability to work in double-pulse mode, it provided versatility in the measurements
leading to increased LIBS signal intensities, improved the signal noise ratio and stabilized spectra. The first test results are
encouraging and demonstrate that this new laser is suitable for integration in compact, portable and low cost LIBS sensors
with a wide spectrum of materials analysis applications.
Q-switched operation of a novel transversely-diode-pumped bulk 1.65μm Er:Yb:YAG laser is demonstrated using a piezoelectric "FTIR" type of Q-switch. Typical output pulses of approximately 12mJ energy and 4011s duration have been obtained, suitable for telemetry and other applications. The material is transversely pumped using quasi-cw 960-nm laser-diode arrays. In Q-switched mode, lasing threshold lies in the range of 0.5-1.4J, depending on pumping conditions and output coupling, while optical slope efficiencies in the order of 1% were measured with respect to the incident pump energy. The reported system represents a rare-earth crystalline laser with superior active material and optical qualities, to challenge the established glass-host materials in the 1.6μm eyesafe wavelength region.
We describe an application of laser cleaning of metallic wheels with a Q-switched Nd:YAG laser. The beam is divided in four parts injected into fibers, sent on an automated machine for stripping the protective varnish on metal sheets, parts of large electrical motors, before soldering of cylindrical spacers via an electrical discharge.
Pulsed Er3+:Yb3+:YAG is a novel crystalline diode-pumped laser capable of delivering high pulse energies in the 1.5-
1.7μm "eye-safe" region. This work reports efficient lasing in long-pulse and in Q-switched mode, with pulse energies in
the order of 10's of mJ, employing standard 960-nm quasi-cw semiconductor laser arrays in a direct transverse diodepumping
configuration. In free-running mode, 83mJ output, 15% slope efficiency and 0.24J pump threshold have been
attained. Q-switched operation was realized with a "frustrated total internal reflection (FTIR)" device, yielding 12.5mJ
single pulses of 41-ns FWHM duration with smooth temporal and spatial profiles. Pump temperature-tuning and pulse
duration effects on laser performance were also investigated, whereas pumping parameters optimizing pulse energy and
efficiency were determined.
We demonstrate efficient lasing of bulk diode-pumped Er3+:Yb3+:YAG at 1.645 µm. 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 has an uncomplicated and compact design, it represents a good crystalline rare-earth candidate system with superior material qualities to compete against the established glass-host materials in the eye-safe wavelength range.
Efficient lasing at 1.645mm of bulk diode-pumped Er3+:Yb3+:YAG is demonstrated. The material is transversely pumped using three quasi-cw 960-nm laser-diode arrays in a simple arrangement. In free-running mode of operation, output pulse energy of 79mJ is obtained at 4.7J of incident optical pump energy. Lasing threshold lies in the range of 1.0-1.9J in long-pulse operation, depending on pumping conditions, while optical slope efficiencies of 2.2-3.4% were measured with respect to the incident pump energy. Furthermore, initial Q-switching experiments with a Co:MALO saturable absorber yielded pulses of 1.7mJ energy and 340ns FWHM duration. As the reported laser setup is also characterized by an uncomplicated and compact design, it represents a good crystalline rare-earth candidate system with superior material qualities to compete against the established glass-host materials in the eyesafe wavelength range.
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