High-power ultrafast GHz laser sources:design and applications

Eric Cormier

The development of laser sources with ultra-high repetition rates had been mainly driven by the telecom industry with a market in quest of high-speed internet access and ever-increasing data throughput. Thanks to the availability of numerous commercial components at the heart of this technology, laser sources able to produce short pulses at tens or hundreds of GHz have been investigated however limited to the telecom wavelength range. The situation is less favorable at other wavelengths such as 1 µm for instance, a wavelength of great interest if high power or high energy is considered, where the Yb technology can be implemented.

We will present recent developments performed in our group around versatile sources able to generate ps pulses at ultra-high repetition rates tunable from 1 to 20 GHz at 1 µm wavelength. These sources are based on electro-optic modulation and feature user controllable and very flexible properties. The systems can operate in burst mode with a given number of pulses per burst and a given burst repetition rate with average powers in excess of 100 W. Hence, burst energy, energy per pulse, pulse peak power, pulse repetition rate, burst repetition, … are all parameters easily controllable over large ranges.

Such developments have been motivated by recent advances in various domains. Such a source allows, for instance, to generated electron wavepackets at GHz repetition rates from a photocathode to be further accelerated in X-Band LINACs. In laser processing, an interesting controversy is taking place on the existence and origin of large discrepancies whether ablation is performed with energetic pulses or burst of GHz pulses. Several other applications will also be presented and discussed.

Prof. Eric Cormier received his Phd degree from the University of Bordeaux and did a postdoctoral position at the Max Planck Institut für Quantenoptik (Germany) developing theories of laser-atom interaction in strong fields. He is now professor of Physics at the University of Bordeaux where he develops ultra-short pulse laser sources for high field physics based on solid-state, fiber or non-linear technologies. Since 2013, he is actively contributing to the large-scale infrastructure ELI-ALPS (Hungary). Prof. Cormier is a member of the Institut Universitaire de France.