Tailored diode laser single emitters with long (6 mm) resonators and wide (1.2 mm) emission apertures that operate with 940 nm emission wavelength were assembled in novel edge-cooled vertically stacked arrays, and used to construct a compact and highly efficient fiber coupled pump source for Yb:YAG pulsed high-energy class solid-state lasers. The novel configuration is shown to allow repetition rates of 200 Hz at 1 ms pulse duration, at an output power of 130 W per single emitter. The emission of two stacked arrays was then optically combined to realize pump modules that deliver 6 kW peak power (pulse energy 6 J) from a 1.9 mm core diameter fiber, with wall plug efficiency of 50%. This represents a significant improvement in terms of duty cycle and electro-optical efficiency over conventional sources. The pump module has been successfully tested at the Max Born Institute, Berlin during trials for pumping of disk lasers.This work was funded in part via the European Regional Development Fund (ERDF) under contract number 20072013 2/42.
The deformable mirror with the size of 410 mm468 mm controlled by the bimorph piezoceramic plates and multilayer piezoceramic stacks was developed. The results of the measurements of the response functions of all the actuators and of the surface shape of the deformable mirror are presented in this paper. The study of the mirror with a Fizeau interferometer and a Shack–Hartmann wavefront sensor has shown that it was possible to improve the flatness of the surface down to a residual roughness of 0:033 mm (RMS). The possibility of correction of the aberrations in high-power lasers was numerically demonstrated.
Further advancement of high-energy pulsed lasers requires a parallel development of appropriate optical components. Several different optical components, such as mirrors and antireflection-coated windows, which are essential for the design of HiLASE high average power lasers were tested. The following paper summarizes results on the measurements of laser-induced damage threshold of such components, and clearly shows their capabilities and limitations for such a demanding application.This work is co-financed by the European Regional Development Fund, the European Social Fund and the state budget of the Czech Republic (project HiLASE: CZ.1.05/2.1.00/01.0027, project DPSSLasers: CZ.1.07/2.3.00/20.0143, project Postdok: CZ.1.07/2.3.00/30.0057). This research was partially supported by the grant RVO 68407700.
Laser drivers are an enabling factor to inertial confinement fusion, because laser diodes must be used instead of flash lamps. We discuss the limitations of laser diode arrays and show what steps the industry is taking. The pump power requirements of large-scale projects such as LIFE or HiPER are within reach of semiconductor laser diode assemblies. Pulsed light output powers per laser bars have been around 300Wper bar, as in the Jenoptik 940 nm bars previously used for pumping the Yb:YAG slabs in the DiPOLE project. By redesigning the semiconductor laser structures 500W per bar is now commercially available for 808, 880 and 940 nm pump wavelengths. The construction of one inertial fusion power plant will require an amount of semiconductor laser chips in excess of the current annual production by two orders of magnitude. This adds to the engineering task of improving the device characteristics a challenge to production capacity. While the industry benefits from the recent boost in solid-state lighting that acts as a technology driver, cooperation between manufacturers will be imperative, and to this end we propose standardization efforts.
Using cryogenic laser technology, it is now possible to design and demonstrate lasers that have concomitant high average and peak powers, with near-diffraction-limited beam quality. We refer to these new laser systems as HAPP lasers. In this paper, we review important laser crystal materials properties at cryogenic temperature, with an emphasis on Yb lasers, and discuss the important design considerations, including the laser-induced damage threshold, nonlinear effects and thermal effects. A comprehensive model is presented to describe diode pulsed pumping with arbitrary duration and repetition rate, and is used with the Frantz–Nodvik equation to describe, to first order, the performance of HAPP laser systems. A computer code with representative results is also described.
We present the workflow of the design, realization and testing of deformable mirrors suitable for high power diode pumped solid-state lasers. It starts with the study of the aberration to be corrected, and then it continues with the design of the actuators position and characteristic. In this paper, we present and compare three deformable mirrors realized for multi-J level laser facilities. We show that with the same design concept it is possible to realize deformable mirrors for other types of lasers. As an example, we report the realization of a deformable mirror for femtosecond lasers and for a CW CO2 laser.Regional Development Fund, the European Social Fund and the state budget of the Czech Republic (project HiLASE: CZ.1.05/2.1.00/01.0027, project DPSSLasers: CZ.1.07/2.3.00/20.0143). This research was partially supported by the grant RVO 68407700.