Torsten Mans

Compact diode-pumped 1.1 kW Yb:YAG Innoslab femtosecond amplifier.

We demonstrate a compact diode-pumped Yb:KGW femtosecond oscillator-Yb:YAG Innoslab amplifier master oscillator power amplifier (MOPA) with nearly transform-limited 636 fs pulses at 620 W average output power, 20 MHz repetition rate, and beam quality of M(x)(2) = 1.43 and M(y)(2) = 1.35. By cascading two amplifiers, we attain an average output power of 1.1 kW, a peak power of 80 MW, and a 615 fs pulse width in a single linearly polarized beam. The power-scalable MOPA is operated at room temperature, and no chirped-pulse amplification technique is used.

Hybrid 400W Fiber-Innoslab fs-Amplifier

Combining fiber- and Innoslab technology enables up to 420W average output power at almost diffraction limited beam quality. Pulses compressible to τ=720 fs at 1MHz and 100kHz repetition rate have been achieved so far.

High power Yb:YAG Innoslab fs-amplifier

For high throughput applications a diode-pumped Yb:YAG Innoslab fs-amplifier, scalable to several 100 W, was realized. At 63.2 MHz repetition rate and 77 W average output power nearly transform and diffraction limited 786 fs pulses are achieved so far.

1100 W Yb:YAG femtosecond Innoslab amplifier

Laser sources of high average power are essential to transfer femtosecond technology to industrial applications. We demonstrate a compact diode-pumped Yb:KGW femtosecond oscillator-Yb:YAG Innoslab amplifier MOPA with nearly transform and diffraction limited 636 fs pulses at 620 W average output power and 20 MHz repetition rate. By cascading two amplifiers an average output power of 1.1 kW and peak power of 80 MW is achieved in a single, linearly polarized beam. The MOPA is operated at room temperature and no CPA technique is used. The specific properties of Innoslab MOPAs are compared with fibers and thin-disks.

Highly efficient diode-end-pumped Nd:YAG slab laser

High power diode pumped solid state lasers are auspicious sources for various applications in material processing. The solid state laser we report on is a Nd:YAG slab laser, that is partially end pumped from two ends by the line focus of two diode laser stacks. The pumped volume has a rectangular cross section. The resonator is configured, so that it is stable in the plane of small dimension and off axis unstable in the plane of large dimension of the gain cross section. Unlike conventional slab laser design, in which the laser beam takes zick zack path inside the slab crystal, in the present design the beam goes straight through the crystal with perpendicular end faces.

Power scaling of ytterbium INNOSLAB amplifiers beyond 100W average power

The Innoslab design, already established for neodymium doped laser materials, 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. A compact diode-pumped Yb:YAG Innoslab fs-oscillator-amplifier system, scalable to the kilowatt range, was realized. Nearly transform and diffraction limited 682 fs pulses at 400W average output power and 76 MHz repetition rate at room temperature and without using CPA technique have been achieved so far.

High-Average Power Ultrafast Yb:Innoslab-Amplifier

The state of the art of Yb:Innoslab femtosecond amplifiers is presented. Diode-pumped Innoslab amplifiers are designed for a good thermal management and low nonlinearity and enable ultrafast laser systems with high average power and almost diffraction limited beam quality. The presented compact femtosecond oscillator-Yb:Innoslab amplifier MOPA provide nearly transform and diffraction limited 640 fs pulses at 620 W average output power and 20 MHz repetition rate. By cascading two amplifiers an average output power of 1.1 kW and peak power of 80 MW is achieved in a single, linearly polarized beam. The specific properties and scaling laws of Yb:Innoslabs are discussed.

Femtosecond Innoslab amplifier with 300W average power and pulse energies in the mJ-regime

We demonstrate a femtosecond Yb:YAG InnoSlab laser amplifier producing <3mJ pulse energy at 100kHz pulse repetition rate. The minimal pulse duration is <1ps resulting in pulse powers <3GW. High energy and high average power could be obtained with the use of chirped pulse amplification on the power amplifier end. The laser setup consists of a seed laser with 10mW average power at pulse repetition rates of 100kHz to 1MHz, a pre-amplifier stage, a highpower InnoSlab-amplifier stage and a grating based pulse compressor. This laser source is suited for pumping of OPCPA setups und parallelisation of applications in materials processing.

High-power ultra-short pulse laser radiation: New sources as key enablers for emerging applications

Ultrafast laser sources with pulse durations in the sub-picosecond regime enable a precise machining of various materials. Pulse durations shorter than the electron phonon-coupling time lead to a low thermal load or even non-thermal ablation processes. Exploiting non-linear absorption processes, the absorption becomes nearly material independent when laser pulses of several microjoule energy and high beam quality are focused on the materials surface. Low pulse energies and intensities well above the vaporization threshold and therefore an eduction of the absorbed energy within the ablation product enables a high-precision cutting, ablation and drilling of, even weakly absorbing materials, multi-component and multi-layer systems. Additional, the focusing of ultrafast laser pulses in the volume of transparent dielectrics allows a localized modification of the bulk material. Specifically, defined refractive index changes in glasses and crystals can be utilized for waveguiding and beam-forming applications. A combined approach of material modification followed by chemical etching provides the possibility to manufacture micro-channels or 3D-micro mechanical parts. The 3D-capability of the in-volume material processing originates from the non-linear absorption of light in the initially transparent material.To achieve high process efficiencies in material processing, laser sources delivering high average power are necessary. High average power is achieved either by high pulse energies and low repetition rates or high pulse repetition rates and moderate pulse energies. The optimum set of parameters is strongly depending on the process, the material and the application. In this paper, we present compact laser sources with a high flexibility in pulse energy and pulse repetition rate and an average power of several hundreds of Watt. Additional, a broad range of applications, from micro- and nanostructuring of various materials to volume processing of dielectrics will be presented.Ultrafast laser sources with pulse durations in the sub-picosecond regime enable a precise machining of various materials. Pulse durations shorter than the electron phonon-coupling time lead to a low thermal load or even non-thermal ablation processes. Exploiting non-linear absorption processes, the absorption becomes nearly material independent when laser pulses of several microjoule energy and high beam quality are focused on the materials surface. Low pulse energies and intensities well above the vaporization threshold and therefore an eduction of the absorbed energy within the ablation product enables a high-precision cutting, ablation and drilling of, even weakly absorbing materials, multi-component and multi-layer systems. Additional, the focusing of ultrafast laser pulses in the volume of transparent dielectrics allows a localized modification of the bulk material. Specifically, defined refractive index changes in glasses and crystals can be utilized for waveguiding and beam-forming applications. A...

Compact high Power Ytterbium based fs-Oscillator-Amplifier System

A compact diode-pumped Yb:YAG Innoslab fs-oscillator-amplifier system, scalable to several 100W, was realized. Nearly transform and diffraction limited 786fs pulses at 77W average output power and 63.2MHz repetition rate are achieved so far.