Study of laser damage mechanisms in the sub-picosecond regim

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In the development of femtosecond lasers and their applications, laser-induced damage to optical components is a main limitation. This issue inhibits the available power and long-term resistance of short-pulse laser systems and
affects the efficiency of many applications in the scientific, industrial and medical field. In these systems the coatings are often the weakest part when the laser damage resistance is concerned. Strong effort of fundamental
research in the field of thin films is then necessary to increase the lifetime of the coatings. Progress on this particular topic requires available experimental data on the laser-induced damage threshold (LIDT) of optical coating materials and fundamental knowledge of the laser damage mechanisms.

sub-picosecond laser damage on a multilayer stack

In this context, the work of the group is focus on experimental and fundamental studies of high power laser/matter interactions in optical coating
materials. Indeed, despite common characteristics with bulk materials, the laser damage of dielectric thin films has peculiarities that need to be taken into account: specific optical, mechanical, thermal, and electronic properties affecting the resistance of components under laser exposition, these properties being very dependent on the deposition conditions. The objectives are to progress in the understanding of the basic mechanisms of laser/matter interaction in optical coatings materials and systems submitted to high power, short pulse lasers. Additionnaly the group collaborates with coating manufacturers (companies and laboratories) to produce fonctional high power coatings.

Different laser damage mechanisms in the case of thin films: thermal effects (evaporation, melting), mechanical effects (thermomecanical stress, shock wave), Coulombian explosion (charge repulsion), Plasma scald, ripples

Laser Induced Damage Threshold of more than 60 different optical thin film materials (500fs, 1on1, 1030nm)

References of our works on this subject :

  • Mende M., Schrameyer S., Ehlers H., Ristau D., Gallais L., ’Laser damage resistance of ion-beam sputtered Sc2O3/SiO2 mixture optical coatings’, Applied Optics, 52 1368-1376 (2013).
  • Mangote B., Gallais L., Commandré M., Mende M., Jensen L., Ehlers H., Jupé M., Ristau D., Melninkaitis A., Mirauskas J., Sirutkaitis V., Kičas S., Tolenis T., Drazdys R., ’Femtosecond laser damage resistance of oxide and mixture oxide optical coatings’, Optics Letters, 37 1478 (2012).
  • Mangote B., Gallais L., Zerrad M., Lemarchand F., Gao L.H., Commandré M., Lequime M., ’A high accuracy femto-/picosecond laser damage test facility dedicated to the study of optical thin films’, Review of Scientific Instruments, 83 013109 (2012).
  • Gallais L., Mangote B., Zerrad M., Commandré M., Melninkaitis A., Mirauskas J., Jeskevic M., Sirutkaitis V., ’Laser-induced damage of hafnia coatings as a function of pulse duration in the femtosecond to nanosecond range’, Applied Optics, 50 9 C178-187 (2011)
  • Melninkaitis A., Tolenis T., Mažulė L., Mirauskas J., Sirutkaitis V., Mangote B., Fu X., Zerrad M., Gallais L., Commandré M., Kičas S., Drazdys R., ’Characterization of zirconia– and niobia–silica mixture coatings produced by ion-beam sputtering’, Applied Optics, 50 9 C188-196 (2011)
  • Gallais L., Mangote B., Comandré M., Melninkaitis A., Mirauskas J., Jeskevic M., Sirutkaitis V., ’Transient interference implications on the subpicosecond laser damage of multidielectrics’, Applied Physics Letters, 97 051112 (2010)