POEYDEBAT Etienne: Development of a Mamyshev oscillator.
Thesis summary: For several years, the Center for Scientific and Technological Studies of Aquitaine (CESTA) has hosted Laser Mega Joule (LMJ) and Petawatt Aquitaine Laser (PETAL) installations as part of the Simulation program launched by the Military Applications Department. (DAM) of the Commissariat for Atomic Energy and Alternative Energies (CEA). PETAL is an ultra-high intensity laser based on a frequency drift amplification technique: an ultra short pulse is stretched temporally and then amplified in an amplifying section made of neodymium doped glass before being temporally compressed and then focused on center of an experiment chamber to achieve very high intensities of the order of 1021W / cm².
Currently, the oscillator found at the very beginning of the string on the PETAL installation and delivering this ultra short pulse is a Ti: Sa source (titanium doped sapphire) mode locking by Kerr lens. It is a free-space technology that is difficult to use and requires regular maintenance (provided by a company outside the CEA) and which dates from the mid-1980s. In order to overcome these drawbacks, the The ideal is to design a fully fiber laser source because it has the advantage of being robust, compact, reliable and therefore requires little or no maintenance.
A new fiber oscillator architecture presented recently: the Mamyshev oscillator, is able to deliver pulses whose peak powers surpass those reached with a source Ti: Sa. This oscillator designed to operate in strongly non-linear regime is capable of to reach energies of the order of one hundred nanojoule with broad-spectrum impulses, over a period of about ten femtoseconds.
The goal of my thesis is to design and develop a Mamyshev-type source to meet the specific needs of PETAL. This work is carried out in collaboration with the laboratory of PhLAM (Laser Physics, Atoms and Molecules) with which the DLP (Laser Power Department) of CEA CESTA works for years.
OPOKU Richard Asamoah - e.poeydebathotmail com
Thesis director: BOUWMANS Géraud
Co-directors: HUGONNOT Emannuel