A kilowatt diode-pumped solid-state heat-capacity double-slab laser

A kilowatt diode-pumped solid state heat capacity laser is fabricated with a double-slab Nd:YAG. Using the theoretical model of heat capacity laser output laser characteristics, the relationships between the output power, temperature and time are obtained. The slab is 59 x 40 4.5mm(3) in size. The average pump power is 11.2kW, the repetition rate is 1kHz, and the duty cycle 20%. During the running time of 1s, the output energy of the laser has a fluctuation with the maximal output energy at 2.06J, and the maximal output average power is 2.06kW. At the end of the second, the output energy declines to about 50% compared to the beginning. The thermal effects can be improved with one slab cooled by water. The experimental results are consistent with calculation data.

GaAs absorber grown at low temperature used in passively Q-switched diode pumped solid state laser

We report, for the first time to the best of our knowledge, on a passively Q-switched Nd:YVO4 laser with a GaAs absorber grown at low temperature (LT) by metal organic vapor phase expitaxy. Using the LT GaAs absorber as well as an output coupler, a passively Q-switched laser whose pulse duration is as short as 90 ns, was obtained.

Raman spectra of polymethyl methacrylate optical fibres excited by a 532 nm diode pumped solid state laser

Polymethyl methacrylate (PMMA) optical fibres are fabricated by a preform drawing process. The Raman spectra of PMMA fibres are recorded using a diode pumped solid state laser emitting at 532 nm and a CCD-spectrograph in the 400–3800 cm−1 range. The variation of the Raman intensity with the length of the optical fibre is studied. Investigations are carried out on the variation of FWHM of the Raman peak at 2957 cm−1 with the length of the optical fibre and pump power. The differential scattering cross section and gain coefficient of the Raman peak at 2957 cm−1 in PMMA are calculated in relation to that of toluene.

Raman spectra of polymethyl methacrylate optical fibres excited by a 532 nm diode pumped solid state laser

Polymethyl methacrylate (PMMA) optical fibres are fabricated by a preform drawing process. The Raman spectra of PMMA fibres are recorded using a diode pumped solid state laser emitting at 532 nm and a CCD-spectrograph in the 400–3800 cm−1 range. The variation of the Raman intensity with the length of the optical fibre is studied. Investigations are carried out on the variation of FWHM of the Raman peak at 2957 cm−1 with the length of the optical fibre and pump power. The differential scattering cross section and gain coefficient of the Raman peak at 2957 cm−1 in PMMA are calculated in relation to that of toluene

Dynamic analysis of V-folded cavity for TEM00 operation of end-pumped solid-state laser

Based on graphic analysis design method of optical resonator, a simple design expression of V-folded cavity of end-pumped solid-state lasers with TEM00 operation is described, which satisfies two criterias of the resonator design. We give numerical simulation of spot size as a function of thermal focal length using this design approach whose advantages are validated experimentally.

Theoretical study on longitudinally pumped Yb3+:Y2O3 lasers

To optimize the performance of longitudinally pumped Yb^(3+):Y2O3 ceramic lasers, cavity parameters such as material length and output coupler transmission at a certain laser output power are calculated numerically using quasi-three-level laser model. The results show great potential of Yb^(3+):Y2O3 ceramics for highly efficient diode-pumped solid-state lasers.

Dynamics of free-running, pump-modulated and coupled semiconductor and solid-state lasers

The output of a laser is a high frequency propagating electromagnetic field with superior coherence and brightness compared to that emitted by thermal sources. A multitude of different types of lasers exist, which also translates into large differences in the properties of their output. Moreover, the characteristics of the electromagnetic field emitted by a laser can be influenced from the outside, e.g., by injecting an external optical field or by optical feedback. In the case of free-running solitary class-B lasers, such as semiconductor and Nd:YVO4 solid-state lasers, the phase space is two-dimensional, the dynamical variables being the population inversion and the amplitude of the electromagnetic field. The two-dimensional structure of the phase space means that no complex dynamics can be found. If a class-B laser is perturbed from its steady state, then the steady state is restored after a short transient. However, as discussed in part (i) of this Thesis, the static properties of class-B lasers, as well as their artificially or noise induced dynamics around the steady state, can be experimentally studied in order to gain insight on laser behaviour, and to determine model parameters that are not known ab initio. In this Thesis particular attention is given to the linewidth enhancement factor, which describes the coupling between the gain and the refractive index in the active material. A highly desirable attribute of an oscillator is stability, both in frequency and amplitude. Nowadays, however, instabilities in coupled lasers have become an active area of research motivated not only by the interesting complex nonlinear dynamics but also by potential applications. In part (ii) of this Thesis the complex dynamics of unidirectionally coupled, i.e., optically injected, class-B lasers is investigated. An injected optical field increases the dimensionality of the phase space to three by turning the phase of the electromagnetic field into an important variable. This has a radical effect on laser behaviour, since very complex dynamics, including chaos, can be found in a nonlinear system with three degrees of freedom. The output of the injected laser can be controlled in experiments by varying the injection rate and the frequency of the injected light. In this Thesis the dynamics of unidirectionally coupled semiconductor and Nd:YVO4 solid-state lasers is studied numerically and experimentally.

Quasi-self-imaging planar waveguide lasers with high-power single-mode output

We describe high-power planar waveguide laser which can achieve single-mode output from a multi-mode structure. The planar waveguide is constructed with incomplete self-imaging properties, by which the coupling loss of each guided mode can be discriminated. Thermal lens effects are evaluated for single-mode operation of such high-power diode-pumped solid-state lasers. (c) 2005 Elsevier B.V. All rights reserved.

Pseudo-nonlinear and athermal lensing effects on transverse properties of Cr(3+) based solid-state lasers

Several experiments (time-resolved Z-scan experiments based on pulsed and CW pump lasers, time-resolved divergence diagnostics) have been performed to examine and clarify the question of the converging or diverging population lensing effect occurring in a Cr(3+):Al(2)O(3) ruby laser. The dynamics of the laser far-field divergence of such a laser indeed indicated initially a diverging effect while Z-scan measurements conclude to a converging one. The origin of this discrepancy is thus analysed and elucidated here by introducing the general concept of correlation collapse between the centre and the wings of a laser beam having some clipping. (C) 2010 Elsevier B.V. All rights reserved.