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Coherent beam combining (CBC) is an efficient way to scale the brightness of laser arrays. We demonstrate the active phase locking CBC of two slab laser amplifiers based on the multi-dithering technique. The experimental investigation on the 102 W coherent beam combining of two slab amplifiers shows that the whole system in a closed loop performs well over a long time observation. The contrast of the coherent combined beam profile is about 87% and the combining efficiency is nearly 85%. In addition, the CBC of two green lasers is realized based on the second-harmonic generation of the phase locking pump lasers. To the best of our knowledge, this is the first report about second-harmonic active phase locking, which indicates further potential applications of CBC.

A diode-side-pumped Nd:YAG ceramic slab laser with a high power output is presented. An average power of 526 W is achieved at 1064 nm with a repetition rate of 120 Hz and a pulse width of 180 μs from a 93mm × 52mm × 8 mm ceramic slab at a pump power of 1928 W, corresponding to an optical-to-optical efficiency of 27.3%.

We present an 880-nm laser-diode partially end-pumped Nd:YVO4 slab cw laser with output 126.7 W by using a hybrid resonator. The slop efficiency and optical-to-optical efficiency with respect to absorbed pumping power are 73.2% and 58.7%, respectively. At the output power of 100 W, the beam propagation M2 factors are 1.1 in the unstable direction and 1.15 in the stable direction.

The thermal conduction theory based on uniform heating in the slab laser has been presented before, but results from the theory are very different from the results of experiments. In this paper, a non-uniform heating model based on the absorption law of the medium is proposed. According to the model, the temperature distribution in the slab laser under CW and pulse pumping is solved. Thermal stress and fracture limitation of the slab are given. The new model is in good accordance with the experimental results.

It is well known that improving laser crystal properties is of importance for the laser applications. Recently, a new laser crystal, i.e., YAG doped with Nd+3 and Ce+3 ions has been developed in China. In this paper we report our experimental results with (Nd,Ce):YAG laser including rod and slab laser performance, and Q-switched operation characteristics.

We have designed a diode pumped Nd:YAG zigzag slab laser test bed. Our goal is to produce 200 to 300 watts of average optical power with good beam quality. It has been tested, to date, to 70 watts average power using a 20% subset of the design pump diodes.

The total-internal-reflection, face-pumped solid state laser (or, simply, the slab laser) has been under development for nearly two decades, since it was first demonstrated by Chernoch and Martin at General Electric [1]. Much of the development has concentrated on the demonstration of systems with near-diffraction-limited performance, which in principal is more readily achieved with the slab laser than with conventional rod-geometry configurations. As Danilov et al have pointed out [2], most of the slab lasers described to date have had considerably lower efficiencies than rod lasers, often the result of pumping-cavity designs chosen for a high uniformity of illumination over the slab surface.

Work in progress at M.I.T. toward construction of a tabletop x-ray laser with a repetition rate on the order of 0.1 Hz is reviewed. Potential collisionally pumped laser schemes in Nilike Mo and Nd-like U are described. The use of whisper gallery mirrors as an oscillator cavity is discussed. The design and construction of a zig-zag slab laser producing 5J in 100 psec pulses with a repetition rate of 0.1-1 Hz is reviewed.© (1990) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A corner_pump method for high_power quasi_three_level lasers is reported. The de sign uses a slab laser configuration with the incident pump light from the slab corner. We present an analytic description of pumping absorption, pumping bright ness, doping concentration and crystal dimension for the corner_pumped composite Yb:YAG laser. In the experiments a maximum continuous-wave output power of 400 W with slope efficiency 28% was achieved. This result shows the validity of corn er_pumping concept and its feasibility in the development of high_power solid_st ate lasers.

An efficient high-power cw Nd:YAG slab laser, partially end pumped by diode-laser stacks, and a novel beam-shaping technique are reported. The optical efficiency amounted to 44 per cent, and the slope efficiency amounted to 55 per cent. Introducing an intracavity Brewster plate to polarize the laser beam, we obtained an optical efficiency of 35 per cent and a slope efficiency of 41 per cent. The output beam was rectangular and the beam quality asymmetric in two orthogonal directions. To equalize the beam quality, we introduced a step. mirror beam-shaping technique. The beam-shaping technique and the results obtained are discussed.

A novel miniature slab laser design is described that is compact and easily manufactured and provides short Q-switched pulses with high efficiency at low pump inputs. Through the use of a coplanar-pumped folded slab geometry it combines some of the advantages of end pumping, such as good pump/mode matching, with some of those of side pumping, such as scalability and simplicity. It is suitable for pumping with either cw or quasi-cw diodes and has been operated efficiently in Q-switched, cw, and high-repetition-rate Q-switched modes. The slab is uncoated, reducing complexity and cost as well as parasitic oscillations. The cw slope efficiency is 57%.

The thermal conduction theory based on uniform heating in the slab laser has presented before, but the results obtained from this theory disagree considerably from the results of experiment. In this paper, a non-uniform heating model based on the absorption law of medium is proposed. According to this model, the temperature distribution in the slab laser under CW and pulse pumping is solved. Thermal stress and fracture limitation of the slab are given. The new model is in accordance with the experimental results.

The scaling-up of conventional rod solid state lasers, in size and average power,, is limited by the thermally induced gradients and stresses in the laser medium [1] [2] [3].

A face polished, face pumped and face cooled slab laser in which the optical path inside the gain medium undergoes total internal reflection, the effect of the thermal-optical distortions can be reduced1–5. Then, a viewpoint on slab lasers having intrinsic pseudo-phase-conjugate properties was proposed and some demonstrations were given6.

We review the application of flashlamps to the optical pumping of slab laser devices. In particular, pumping configurations, operating regimes, and the impact of well-known flashlamp performance limitations will be reviewed. The operation of slab laser devices in the stress-limited and pump-limited regimes will be delineated. We also present for the first time a theory of flashlamp failure based upon Wiebull fracture statistics and derive expressions for the thermally induced and hoop stress components in the wall of flashlamps.

Using novel liquid cooled slab laser amplifier technology we have developed laser systems capable of amplifying nanosecond laser pulses to energy of ~1 kJ at repetition rate up to 0.1 Hz. The design and performance of these liquid cooled amplifiers at 18 cm aperture will be described along with plans to scale this technology to larger aperture and higher repetition rate.