https://ris.utwente.nl/ws/files/5345732/Meijer02laser.pdf

Laser Machining by short and ultrashort pulses, state of the art and new opportunities in the age of the photons

The advances and characteristics of high-power diode laser materials processing

An illumination device includes: a light source device adapted to emit an excitation light beam; and a rotating fluorescent plate having a single fluorescent layer adapted to convert a part or whole of the excitation light beam into a fluorescent light beam. The fluorescent light beam includes two or more colored light beams, and the single fluorescent layer is formed on a circular disk, which can be rotated by a motor, continuously along a circumferential direction of the circular disk.

Illumination device and projector

In this paper, we review the developments of crystalline Raman lasers over the past five years. Average powers exceeding 5 W and pulse energies above 1 J in the near infrared have been demonstrated for larger scale devices. There has been a rapid development of all-solid-state sources based on the standard diode-pumped lasers, especially intracavity crystalline Raman lasers, which offer wavelength versatility at high conversion efficiencies (overall diode Stokes optical conversion efficiencies up to 17%) in the near infrared, including the 1.5- mum eye-safe band. Passively Q-switched intracavity Raman lasers based on self-Raman laser materials offer many advantages for miniaturization of short-pulse (1 ns) sources. Intracavity frequency-doubled crystalline Raman lasers have also emerged as practical and versatile sources in the yellow orange region at 1-W power levels with diode-visible efficiencies near 10%. Recent developments of all-solid-state continuous-wave (CW) intracavity crystalline Raman lasers offer many possibilities for the future: intracavity frequency doubling has already resulted in the demonstration of CW visible sources with powers approaching 1 W at 5% diode-visible efficiency.

Crystalline Raman lasers

The Innoslab design, already established for neodymium doped laser crystals, was applied to ytterbium doped laser materials. Recent progresses in brightness of high power diode lasers facilitate efficient pumping of quasi-three-level laser materials. Innoslab amplifiers are compared to competing thin-disk and fiber fs-amplifiers. A compact diode-pumped Yb:YAG Innoslab fs-oscillator-amplifier system, scalable to the kilowatt range, was realized. Numerical simulations result in conditions for high efficiency and beam quality. Nearly transform and diffraction limited 680 fs pulses at 400 W average output power and 76 MHz repetition rate without using CPA technology have been achieved at room temperature so far.

400W Yb:YAG Innoslab fs-Amplifier.

A Nd:YAG slab is partially end pumped by a diode laser stack with three diode laser bars. The pumped volume has a rectangular cross section. A hybrid resonator, which is stable in the plane of small dimension and is off-axis unstable in the plane of large dimension of the gain cross section, was used to yield highly efficient laser operation at diffraction-limited beam quality. The laser design and experimental results are reported.

Partially end-pumped Nd:YAG slab laser with a hybrid resonator

We report on a compact and highly efficient diode-end-pumped TEM00Nd:YVO4 slab laser with an output power of 103 W and beam quality M2≦1.5. The optical-to-optical efficiency was 41.5%. In electro-optically Q-switched operation, 83 W of average power at a pulse-repetition rate of 50 kHz with a pulse length of 11.3 ns was obtained. At a pulse-repetition rate of 10 kHz, 5.6 mJ of pulse energy, and 870 kW of peak power were measured.

Electro-optically Q-switched Nd:YVO4 slab laser with a high repetition rate and a short pulse width

The invention concerns an arrangement for shaping the geometrical cross-sion of a radiation field of a plurality of solid and/or semiconductor laser, in particular a plurality of diode laser arrays or field arrangements whose beam-outlet openings extend in a direction lying in the x-y plane and whose ray beam is radiated in the z direction, the x, y and z directions establishing a rectangular co-ordinate system, with an optical structure for generating a defined cross-section for a radiation field. The optical structure comprises reflective elements onto which the radiation of the respective lasers or laser field arrangements is guided and at which the radiation is reflected. The arrangement according to the invention is characterized in that each laser or laser field arrangement both in the x direction and in the y direction; and in that the reflection surfaces of the reflective elements are disposed in planes which are mutually offset and/or tilted such that the radiation portions reflected by the reflection surfaces are mutually offset perpendicular to the radiation diffusion direction with respect to the offset of the radiation outlet surfaces.

Device for providing the cross-section of the radiation emitted by several solid-state and/or semiconductor diode lasers with a specific geometry

We demonstrate a compact, efficient Nd:YVO4 stable-unstable hybrid slab oscillator that was partially end pumped at 880 nm. A maximum output power of 165 W at 1064 nm was obtained with an optical-to-optical efficiency from absorbed pump power to laser output of up to 60% and a slope efficiency of up to 66%. The beam propagation factors M2 were 1.7 in the stable direction and 1.4 in the unstable direction without sidelobes.

Keming Du

Papers

Partially end-pumped Nd:YAG slab laser with a hybrid resonator

Electro-optically Q-switched Nd:YVO4 slab laser with a high repetition rate and a short pulse width

Device for providing the cross-section of the radiation emitted by several solid-state and/or semiconductor diode lasers with a specific geometry

High efficiency 165 W near-diffraction-limited Nd:YVO(4) slab oscillator pumped at 880 nm.

Thermal effects of the diode end-pumped Nd:YVO4 slab